conversation

[san2612]

_Ann:...........................?
_Tom: "Not bad, you?"

A : WHat are you?
B: How do you do?
C: Are you doing OK?
D: What are you doing these days?

I chose B but the answer is C. Why?

[san2612]

Do you mean answer C (Are you doing OK?) is correct? because "how do you do" is not a question but a greeting .