Question

—— How do you do ？
—— ___________________

1. A.
   How are you ?
2. B.
   How do you do ?
3. C.
   Yes , I am fine
4. D.
   Thank you

Answer 1

B
How do you do ？是初次见面时的问候语，回答的人也用同样的文句 How do you do ？回答。所以答案选B。