Which sentence corrects the error in pronoun-antecedent agreement?

they had a hard time choosing the topic of their project.
students can research any subject they are interested in as long as our subject is related to the city’s history.
we included a lot of photographs in his presentation.
i plan to take our own pictures of interesting old buildings around the city.

They had a hard time choosing the topic of their project.  

Explanation:

They had a hard time choosing the topic of their project.

Explanation:

Pronoun-antecedent agreement refers to the correspondence in number that must be between the subject and its antecedent, which is the noun that the pronoun replaces. As a result, a singular pronoun must coincide with a singular antecedent, while a plural pronoun must correlate with a plural antecedent.

The rest of the choices must be revised like the following:

both inform the reader that faryad and liaqat were not given the chance to tell their version of events at the police station.

hope this