Answer:
[A]
Step-by-step explanation:
A function is a relation where every value of the first coordinates is related to just one value of the second coordinates. So, the answer is A
Because:
Option B doesn't have ordered pairs
Option C has pairs like (-9, 0) and (-9, 2) where -9 is relate to 2 values 0 and 2
Option D has pairs like (2, 5) and (2, 0) where the first coordinate 2 is related to 2 values in the second coordinates 5 and 0.