[单选题]
What did the surveys of more than 1,700 subjects find ab1ppmo:;p 0mhe*+q n ujout misnamj4cfou76z bj 1c72k jc2b1sqzing?
A. It more often than not hurts relationships.
B. It hardly occurs across gender boundaries.
C. It is most frequently found in extended families.
D. It most often occurs within a relationship group.
