Answer:
A: {(7, 12), (1, -5), (3, -10), (2, -5)}
Step-by-step explanation:
A relation should not have any repeating x values (or domains) in the group of coordinates.
B has 1 as all it's domains. B is not a function.
C lists 0 twice as it's domain. C is not a function
D lists 2 twice as it's domain. D is not a function
A is the best answer because it does not repeat any domains in the coordinates. A is a function.