. . . . . . . . a doctor . . . . . . . . in time, the patient can be saved.

A. Had, arrived

B. If, arrives

C. Will, arrive

D. Do, arrive

Answer: Option B

Solution(By Examveda Team)

'if' is used in conditional sentences to introduce the circumstances in which an event or situation might happen, might be happening, or might have happened. 'arrives' is used because of singular subject.