Answer:
Option (A): They had a hard time choosing the topic of their project.
Step-by-step explanation:
To find the sentence which corrects the error in pronoun-antecedent agreement, let's check the options.
For there to be pronoun-antecedent agreement, any or all pronoun(s) used in a sentence must match the subject or object they are replacing.
A) They had a hard time choosing the topic of their project.
the subject of the above sentence is plural (they); this subject is replaced with an object in plural (their). Since both are plural and "their" is the possessive form of "they", this statement corrects the error in pronoun-antecedent agreement.
B) Students can research any subject they are interested in as long as our subject is related to the city’s history.
The subject of the above sentence is plural (students); then later this subject is replaced with two pronouns, both of which are plural (they and our). The "our" creates a pronoun-antecedent error because "our" is a first person possessive. The possessive pronoun, "their" would be appropriate in the sentence as it is the possessive form of "they"
C) We included a lot of photographs in his presentation.
The subject of the above sentence is plural (We) and the object (his) is singular. There is error in pronoun-antecedent agreement.
D) I plan to take our own pictures of interesting old buildings around the city.
The subject of the above sentence is singular ("I") and the object (our) is plural. There is error in pronoun-antecedent agreement.