F: Good morning, what's wrong with you? ,M: My head is killing me. It hurts badly.
(A) F: Just a minute! I do not quite follow what you are saying, would you mind repeating that? (B) F: How long have you been having the slight headache? (C) F: How long have you been unable to fall asleep? (D) F: How long have you been having the headache?
D