Which sentence has an error in pronoun-antecedent agreement? a) the people crying on the lifeboats accidentally left their life-jackets on the ship. b) one of the assistant principals at gradgrind high school is sure to find out who keyed his car. c) each of the students in this room will be responsible for providing their own copy of the novel. d) the tour guide for this portion of the niagara falls experience expects you to tip him generously.