Answer:
C: is a function because each input (x) has exactly one output( y).
Step-by-step explanation:
A function is when one input (x) has exactly one output (y).
A: is not a function because -4 is paired with two different y values.
B: is not a function because -4 is paired with two different y values.
C: is a function because each input (x) has exactly one output( y).
D: is not a function because -1 is paired with two different y values.
