Answer:
The answer is C. a, b, and d only.
Explanation:
A is not a function because -3 has two y like, (-3,-5) and (-3,-3).
B is not a function because like A, it has an x that has more than one y value, like (3,2) and (3,4)
C is a function because all the x values only have one y value, even though there are many x values that contain the same y value but to be a function the x value must not repeat (only if the y value is the same) or have multiple y values for the same x value.
D is not the function because the x value 3 has two different y values, (3,2) and (3,6)