问题:
[单选题]
If we want to proof problem Y can be solved in polynomial-time via a reduction from problem X, which of the following statement is NOT necessary?
AArbitrary instances of problem X can be solved in polynomial-time.
BArbitrary instances of problem X can be solved using polynomial number of calls to oracle that solves problem Y.
CArbitrary instances of problem Y can be solved using polynomial number of calls to oracle that solves problem X.