Answer:
The correct answer is pronouns.
Explanation:
A pronoun is a word that can replace a noun or noun phrase. For example:
* The black cat is hungry. The underlined noun phrase can be substituted by the personal pronoun it.
* Emily likes baking.The proper noun underlined can be susbtituted by the personal pronoun she.
In these examples, you can see that personal pronouns (He,she, it, they, we, I, you) can replace a noun or a noun phrase.
Them (also mentioned in this question) is another type of pronoun. It's called object pronoun. It's going to replace a plural noun in the object position in a sentence. For example: I bought these books for my research. The noun phrase underlined can be replaced by them.
All in all, there are different types of pronouns which are used to replace a noun or noun phrase in a sentence.
