After the patients went into the office,＿＿working.

A.only a doctor did they see

B.only a doctor saw they

C.only a doctor they saw

D.only a doctor had they seen

After the patients went into the office,＿＿working.

1. A.
   only a doctor did they see
2. B.
   only a doctor saw they
3. C.
   only a doctor they saw
4. D.
   only a doctor had they seen