Correct option is C
Doctor → ? (A doctor's primary role should match this relationship.)
Checking the options:
(a) Prescribing → A doctor does this, but it's not the primary role. (False)
(b) Operating → Only surgeons operate, not all doctors. (False)
(c) Curing → A doctor's main purpose is to cure patients. (True)
(d) Diagnosing → Diagnosis is an important step, but curing is the ultimate goal. (False)
Thus, the correct option is (c) Curing