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