Answer:
D{(0, 0), (-1, -0.5), (-2, -1), (-3, -1.5), (-4, -2)}
Explanation:
A function is a relation in which we take every element of the first group and assign an unique element of the second group.
So, the set of ordered pairs that represents y as a function of x is the set that take every value of x and assign an unique value of y.
Then, the set A is not a function because we have the ordered pairs (3,9) and (3,16) in which we have two values of y for the value of x=3.
At the same way, we can said that B and C aren't functions.
Finally, D is the set of ordered pairs that represents y as a function of x because every x has an unique value of y.