Which of the following ratios is not equivalent to 4/8

Since you did not post the answers : p, any of the answers  not consisting of a 1/2 ratio would be incorrect.

i.e:  

correct:
1/2
2/4
3/6
4/8
5/10
6/12
7/14
8/16


wrong:
1/3
4/7
5/12
6/14


hope this !