Which table shows a proportional relationship between x and y?

A.x 1 2 3 4
y 6 8 10 12

B.x 2 4 7 8
y 6 10 21 24

C.x 40 50 60 90
y 8 10 14 18

D.x 4 7 8 10
y 2 3.5 4 5