One result of the family's long ordeal at sea was their appreciation that as a person dehydrates, their
minds tend to wander.
a) their appreciation that as a person dehydrates, their
b) their appreciation that as people dehydrate, their
c) to appreciate that when a person dehydrates, his or her
d) to appreciate that when people dehydrate, their
e) appreciating that as people dehydrate, their
I thought family was Singular so how can it be "their appreciation"?