According to the lecture， there seems to be a；seemingly endless repetition of generation gap between parents and children in the author’s family.It means the generation gap between（）；and that between（）.

A.the author and his sons； his mother and his sons

B.the author and his mother； his grandpa and his mother

C.the author and his mother； the author；and his；sons

D.the author and his sons， his grandpa and his mother

正确答案：the author and his mother； the author；and his；sons