问题

Last month Frank went to Smart China Expo in Chongqing.—_______. And _______.
A:So did he; so did I
B:So he did; so I did
C:So did he; so I did
D:So he did; so did I;
B:So he did; so I did
C:So did he; so I did
D:So he did; so did I;
正确答案是: