Answer:
a. Function.
b. Function
c. Not a function.
d. Function.
Explanation:
A function is a one-to-one or many-to-one relation NOT a one-to-many.
Choice c is not a function because 5 maps to -8 and to 5 ( we have (5, -8) and (5, 5)).
At first I wasn't sure about d. because of the 2 'x values' of -2. But the ordered pairs are the same so it is a function.