Which of the following contains a vague pronoun reference?
A: Jill told her sister that she couldn't go to the film festival because of final exams.
B: Jill said that she couldn't go to the film festival with her sister because of final exams.
The first answer choice contains a vague pronoun reference. The pronoun she could refer to Jill or her sister.
Jill told her sister that she couldn't go to the film festival because of final exams.
The second answer choice shows a possible correction for the vague pronoun reference. The text has been rewritten so that the meaning is clear.
Jill said that she couldn't go to the film festival with her sister because of final exams.