Answer:
1: A (Function)
2: B {(3,2), (2,1), (8,2), (5,7)}
3: C (Domain)
Explanation:
Domains are the x values that go right or left.
Ranges are the y values that go up or down.
If the domain repeats when given a set of points, it is not a function.
The domain (x value) CAN'T repeat.