Answer:
NOT a function
Step-by-step explanation:
a function exists when every unique x input has a unique y output.
here every x less than 0 has two y values.
Answer: C
Step-by-step explanation:
A function only exists if each x-value has only one possible y-value.
C is the only function because each x-value has only one y-value.
The other answer choices have x-values that have multiple y-values. In answer choice A, it has (2,9) and (2,8). In answer choice B, the set has (1, 0) and (1,2). And in answer D, it has (1,3) and (1,2)