---------farthers made them have piano lessons.

A.Peter and Ann's B.Peter's and Ann's C.Peter's and Ann D.Peter and Ann

答案选B
A's and B's +复数各自的。。。
A and B's +单宏缓数，共如羡同的。。。渣绝拍
farthers 说明不是共同的父亲