Lets take a look.
1/3 x 5/5 = 5/15, so it is not A.
1/3 x 7/7 = 7/21, so it is not B.
1/3 x 9/9 = 9/27, so it is not D.
The answer must be C: 6/24, because 1/3 x 6 = 6/18, not 6/24. 1/3 x 8 = 8/24, not 6/24.
