单选题：Let X be a problem that belongs to the class NP. Then which one

Let X be a problem that belongs to the class NP. Then which one of the following is **TRUE**? @[C](2)

A. There is no polynomial time algorithm for X.
B. If X can be solved deterministically in polynomial time, then P = NP.
C. If X is NP-hard, then it is NP-complete.
D. X may be undecidable.





A.There is no polynomial time algorithm for X.
B.If X can be solved deterministically in polynomial time, then P = NP.
C.If X is NP-hard, then it is NP-complete.
D.X may be undecidable.


答案：C