Which relation is also a function?

The answer is A

I put D bc someone said it was D and i got it wrong and it showed the answer was A so yeah ;-;

. + λrh() e 1 1 2 4 4 4 4 4 3 4 4 4 4 4 + th−1(− s(x)2 dx ω + λrh−1() e 2 1 2 4 4

step-by-step explanation: