For each answer, we can plug in the given points:
A) is technically the same as B), but B) expresses correct function notation.
B) 5 = 5(1)
⇒ 5 = 5
25 = 5(2) ⇒ 25 ≠ 10
B) is incorrect.
C) I'm not sure what you mean y=5^5=x, but I'm going to use

because it's close to what you wrote:

The function

works for the points given.
D) 5 = 1 + 5 ⇒ 5 ≠ 6
D) is not correct.
Please check your functions; I'm not sure that C) is a function. In any case, the answer is C) because all the other answers are wrong.