Select all the correct answers.
Which relations are functions?

A:
x y
-2 -4
-2 -6
0 -8
2 -10

B:
x y
0 4
10 5
20 6
10 7

C:
x y
2 -10
1 -20
0 -10
-1 -20

D:
x y
2.5 0
3.5 4
4.5 8
6.5 12

E:
x y
-10 4
-20 5
0 6
-10 7