Divide x by Y for each set if they all have the same value they are proportional:
A: 3/1 = 3, 6/2 = 3, 9/3 = 3 This is proportional.
B: 2/4 = 1/2, 4/6 = 2/3, 7/9 = 7/9, Not proportional.
C: 1.5/3 = 1/2, 3/6 = 1/2, 4/8 = 1/2 This is proportional.
D: 3/1 = 3, 4/3 = 1 1/3, 8/6 = 1 1/3, Not proportional.
The answers are A and C are proportional.
