问题

I often ________ my old friends by email.
A:have you; No, I haven't
B:haven't you; No, I haven't
C:have you; Yes, I have
D:haven't you; Yes, I have;
B:haven't you; No, I haven't
C:have you; Yes, I have
D:haven't you; Yes, I have;
正确答案是: