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.

Plural Subject Plural Verb:  If the subject is plural, the verb must also be plural. There are some special cases.

A) If two or more singular nouns are joined by conjunction 'and' the plural form of verb is used.

• A car and a bike are the two means of transportation.

B)  If we are referring to the members of the unit individually, the plural form of verb is used.

• The cast have been practicing their lines.

In the question : -

1. The rich __________ generally unkind to the food .

In this sentence , the subject the rich sometimes an adjective but it is used as a noun. It is preceded by 'the' which means 'people' . (The rich = people who are rich ). Plural verb is required , so we used plural verb are here .

2. The poor ___________ trustworthy.

In this sentence , the subject the rich sometimes an adjective but it is used as a noun. It is preceded by 'the' which means 'people' . (The poor = people who are poor). Plural verb is required , so we used plural verb are here .

Thus , the Correct Option is A , which is 1. Are 2. Are .

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.

Plural Subject Plural Verb:  If the subject is plural, the verb must also be plural. There are some special cases.

A) If two or more singular nouns are joined by conjunction 'and' the plural form of verb is used.

• A car and a bike are the two means of transportation.

B)  If we are referring to the members of the unit individually, the plural form of verb is used.

• The cast have been practicing their lines.

In the question : -

1. They ___________ going to the museum .

In this sentence , the subject is they and it is a plural subject so we use were as plural verb .

2. The flock ____________ running off in every direction.

In this sentence , we are referring to the members of the unit individually, the plural form of verb is used so we used were as plural verb .

3. The police ___________ already here.

In this sentence ,  some nouns such as police but plural in meaning the plural form of verb is used so we used were here as plural verb .

Thus , the Correct Option is B , which is 1. Were 2. Were 3. Were .

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.

Plural Subject Plural Verb:  If the subject is plural, the verb must also be plural. There are some special cases.

A) If two or more singular nouns are joined by conjunction 'and' the plural form of verb is used.

• A car and a bike are the two means of transportation.

B)  If we are referring to the members of the unit individually, the plural form of verb is used.

• The cast have been practicing their lines.

In the question : -

1. Mita and Rita is students of this school .

The correct form of the above sentence is :

Mita and Rita are students of this school .

In this sentence , when two or more singular nouns or pronouns are joined by the conjunction and , we use plural verb are .

2. The Teacher and the Student am present .

The correct form of the above sentence is :

The Teacher and the Student were present .

In this sentence , when two or more singular nouns or pronouns are joined by the conjunction and , we use plural verb were and it denotes the past tense .

3. Some of the pies is missing.

The correct form of the above sentence is :

Some of the pies are missing.

In this sentence , when quantifiers like all , some ,and few , the verb agrees with the noun or pronoun closet to it .

Thus , the Correct Option is B , which is 1. Mita and Rita are students of this school . 2. The Teacher and the Student were present . 3. Some of the pies are missing.