1. b. Today we celebrate Abraham Lincoln, to whom this monument was raised.
This option is correct because it contains the pronoun "whom". "Whom" is an objective pronoun that is used when talking about the object rather than the subject of the sentence. In this case, Abraham Lincoln is the object of the sentence and thus, the objective pronoun "whom" is most accurate when talking about him.
2. c. the speaker
The speaker is the antecedent of the pronoun "her" in the sentence, "Jason and his friends listened to the speaker carefully and then asked her a few
questions."
This is because "her" cannot be the pronoun associated with Jason (a male), nor his friends, because their gender is not specified, and additionally a group of friends (plural) cannot be the antecedent of the singular pronoun "her".
3. c. theirs
a. "hers" cannot be the correct option since Mrs. Chen's friends refused the offer to ride in her car.
b. "they" is also incorrect because the pronoun "they" cannot be used when referring to the friends' cars. We say "their cars" instead of "they cars" because "their" indicates possessiveness, demonstrating that the cars belong to the two friends respectively. This is why option c."theirs" is the correct answer.