Answer:
C
Step-by-step explanation:
if you don't have from same x different outcomes is a function
think that x is a day you count votes, you can not get for the same day different y number of votes ( something is fishy then)
A. not a function because (6, -3) and (6, 3)
B. not a function because (4,7) and (4,2)
C. is a function
D. not a function because (2, -1) (2,1) (2,3)