What is the antecedent for the pronoun shown in this sentence?

Marietta's sister asked if she could borrow the new red sweater that their mother had bought for Marietta's birthday.

A. Marietta

B. sister

C. sweater

D. mother

The correct answer is B. sister

Explanation:

Pronouns are words that substitute nouns in a sentence to avoid repetition. The word they are substituting is their antecedent. In the sentence we are analyzing here, the subject pronoun "she" is being used. Before it, we have Marietta's sister functioning as the subject in the clause "Marietta's sister asked." Who are we talking about, Marietta or her sister? Her sister. What did she ask? If she could borrow the red sweater. When we answer those questions, we can clearly conclude that the pronoun "she" refers to the sister. Also, from the context presented in the rest of the sentence, we see that the sweater belongs to Marietta already, since it was a birthday present. It would only make sense for her sister to borrow it.