英语语法-请问这道题选哪个?为什么?

问题描述:

英语语法-请问这道题选哪个?为什么?
( ) 9.— It’s good to see you again,Agnes.
— This has been our first chance to visit since ———— from Iran.
A.you return B.you returned C.you have returned D.returning

B since是标志,前面是现在完成时,后面是一般过去时