Subject-verb agreement : - Subject-verb agreement is the grammatical rule that the verb or verbs in a sentence must match the number, person, and gender of the subject; in English, the verb needs to match just the number and sometimes the person . Subject-verb agreement, also called “subject-verb concord,” refers to matching the subject and verb of a sentence in tense, aspect, and mood (abbreviated as TAM), which translates to number, person, and gender.

Usage of Indefinite Pronouns in Subject Verb Agreement:  The verbs , indefinite pronouns use depend on whether the indefinite pronouns are singular or plural. We can divide them into three groups: the singular indefinite pronouns use singular verbs and the plural indefinite pronouns use plural verbs. The third group consists of some indefinite pronouns which may be singular or plural. 

A) The singular indefinite pronouns use singular verbs : like another, anybody, anyone, anything, each, either, enough, everybody, everyone, everything, little, much, neither, nobody, no one, nothing, one, other, somebody, someone, something, use singular verbs.

• Everybody wants to be a winner.

In the question : -

1. A rumor has it that either a pet lion or a pet tiger have just escaped from its owner.

The correct form of the above sentence is :

A rumor has it that either a pet lion or a pet tiger has just escaped from its owner. 

In this sentence , the indefinite pronoun like another, anybody, anyone, anything, each, either, enough, everybody, everyone, everything, little, much, neither, nobody, no one, nothing, one, other, somebody, someone, something, use singular verbs . So we use have here .

2. Both the clowns is fighting. 

The correct form of the above sentence is :

Both the clowns are fighting.

 In this sentence,  the pronouns like both, few, many, others, several, use plural verbs . So we use are here .

Thus , the Correct Option is A , which is 1. A rumor has it that either a pet lion or a pet tiger has just escaped from its owner. 2. Both the clowns are fighting. 

Subject-verb agreement : - Subject-verb agreement is the grammatical rule that the verb or verbs in a sentence must match the number, person, and gender of the subject; in English, the verb needs to match just the number and sometimes the person . Subject-verb agreement, also called “subject-verb concord,” refers to matching the subject and verb of a sentence in tense, aspect, and mood (abbreviated as TAM), which translates to number, person, and gender.

Usage of Indefinite Pronouns in Subject Verb Agreement:  The verbs , indefinite pronouns use depend on whether the indefinite pronouns are singular or plural. We can divide them into three groups: the singular indefinite pronouns use singular verbs and the plural indefinite pronouns use plural verbs. The third group consists of some indefinite pronouns which may be singular or plural. 

A) The singular indefinite pronouns use singular verbs : like another, anybody, anyone, anything, each, either, enough, everybody, everyone, everything, little, much, neither, nobody, no one, nothing, one, other, somebody, someone, something, use singular verbs.

• Everybody wants to be a winner.

In the question : -

1.  Everyone _____________ finished his or her homework.

Some indefinite pronouns are particularly troublesome Everyone and everybody (listed above, also) certainly feel like more than one person and they are always singular, though. So we use has here .

2. Neither of the two traffic lights ___________ working.

In this sentence , the pronouns neither and either are singular and require singular verbs even though they seem to be referring, in a sense, to two things. So we use is singular verb .

3. Either ___________ fine with me.

In this sentence , the pronouns neither and either are singular and require singular verbs even though they seem to be referring, in a sense, to two things. So we use is singular verb .

Thus , the Correct Option is D , which is 1. Has 2. Is 3. Is .

Subject-verb agreement : - Subject-verb agreement is the grammatical rule that the verb or verbs in a sentence must match the number, person, and gender of the subject; in English, the verb needs to match just the number and sometimes the person . Subject-verb agreement, also called “subject-verb concord,” refers to matching the subject and verb of a sentence in tense, aspect, and mood (abbreviated as TAM), which translates to number, person, and gender.

Usage of Indefinite Pronouns in Subject Verb Agreement:  The verbs , indefinite pronouns use depend on whether the indefinite pronouns are singular or plural. We can divide them into three groups: the singular indefinite pronouns use singular verbs and the plural indefinite pronouns use plural verbs. The third group consists of some indefinite pronouns which may be singular or plural. 

A) The singular indefinite pronouns use singular verbs : like another, anybody, anyone, anything, each, either, enough, everybody, everyone, everything, little, much, neither, nobody, no one, nothing, one, other, somebody, someone, something, use singular verbs.

• Everybody wants to be a winner.

In the question : -

1. Few are left after they are eaten so many.  

The correct form of the above sentence is :

Few are left after they have eaten so many. In this sentence , indefinite pronouns that are always plural: like both, few, many, others, several, use plural verbs so are is used .

2. Many of the pigeons has contracted the disease .

The correct form of the above sentence is :

Many of the pigeons have contracted the disease . In this sentence , indefinite pronouns that are always plural: like both, few, many, others, several, use plural verbs so have is used .

Thus , the Correct Option is C , which is 1. Few are left after they have eaten so many.  2. Many of the pigeons have contracted the disease .