I think the answer is The perimeter!
You know if something is a function or not because the X will never be used twice in a set. If it is, then it's not a function.
A. Uses -1 twice
B. Uses Nothing twice (good)
C. Uses 0 twice
D. Uses 0 twice
B is your answer
Step-by-step explanation:
-1<x<infinity this is answer I guess