Answer:
C
Step-by-step explanation:
What makes a function is if each input or x-value has EXACTLY one output or y-value.
a. is wrong because the x value 1, has both an output of 1 and 4
b. is wrong because -1 is repeated 4 times with all different outputs
c. is correct because each input has exactly one output. None of the x values repeat itself
d. is wrong because -1 has 2 outputs.
so this is what makes a function and what doesn't. Hope this helps!
