Clause : - A clause is a group of words that contains a subject and a verb that have a relationship. This relationship is crucial; a clause conveys information about what that subject is or is doing, rather than simply being a random grouping of words.

Noun Subordinate Clause: A Noun Clause is a group of words which contains a Subject and a Predicate of its own, and does the work of a Noun.

For Example: I expect to get a prize. [ Expect what ? ]

In the sentence the words, to get a prize, does not contain a Subject and a Predicate of its own. It is therefore a phrase. This phrase is object of the verb expect and hence does the work of a Noun. It is therefore a Noun phrase.

In the question : -

1. Pay careful attention to _______________

.In this sentence , the correct noun clause is What I am going to say as it does the work of noun in a sentence . It is a noun subordinate clause .

2. There were no complaints except ______________ .

In this sentence , the correct noun clause is That the day was too hot as it does the work of noun in a sentence . It is a noun subordinate clause .

3. ____________ is where I live .

In this sentence , the correct noun clause is That building as it does the work of noun in a sentence . It is a noun subordinate clause .

Thus , the Correct Option is A , which is What I am going to say , That the day was too hot , That building .

Clause : - A clause is a group of words that contains a subject and a verb that have a relationship. This relationship is crucial; a clause conveys information about what that subject is or is doing, rather than simply being a random grouping of words.

Noun Subordinate Clause: A Noun Clause is a group of words which contains a Subject and a Predicate of its own, and does the work of a Noun.

For Example: I expect to get a prize. [ Expect what ? ]

In the sentence the words, to get a prize, does not contain a Subject and a Predicate of its own. It is therefore a phrase. This phrase is object of the verb expect and hence does the work of a Noun. It is therefore a Noun phrase.

In the question : -

1. The teacher said that the earth is round .

In this sentence , the correct noun clause is That the earth is round as it does the work of noun in a sentence . It is a noun subordinate clause .

2. Richa asked me what I wanted .

In this sentence , the correct noun clause is What I wanted as it does the work of noun in a sentence . It is a noun subordinate clause .

Thus , the Correct Option is C , which is That the earth is round , What I wanted .

Clause : - A clause is a group of words that contains a subject and a verb that have a relationship. This relationship is crucial; a clause conveys information about what that subject is or is doing, rather than simply being a random grouping of words.

Noun Subordinate Clause: A Noun Clause is a group of words which contains a Subject and a Predicate of its own, and does the work of a Noun.

For Example: I expect to get a prize. [ Expect what ? ]

In the sentence the words, to get a prize, does not contain a Subject and a Predicate of its own. It is therefore a phrase. This phrase is object of the verb expect and hence does the work of a Noun. It is therefore a Noun phrase.

In the question : -

1. ____________  dealt it.

In this sentence , the correct noun clause is Whoever smelt it as it does the work of noun in a sentence . It is a noun subordinate clause.

2. I will give _______________ some thought.

In this sentence , the correct noun clause is What you said as it does the work of noun in a sentence . It is a noun subordinate clause .

3. ________________ is remarkable.

In this sentence , the correct noun clause is That he believes his own story as it does the work of noun in a sentence . It is a noun subordinate clause .

Thus , the Correct Option is B , which is Whoever smelt it , What you said ,  That he believes his own story .