Answer:
The correct answer is pronouns.
Explanation:
A pronoun is a word that can replace a noun or noun phrase. For example:
* <u>The black cat</u> is hungry. The underlined noun phrase can be substituted by the personal pronoun it.
* <u>Emily</u> 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.
<em>Them</em> (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 <u>these books</u> for my research. The noun phrase underlined can be replaced by<em> them</em>.
All in all, there are different types of pronouns which are used to replace a noun or noun phrase in a sentence.