Remark
If you don't know, you have no choice but to try them all.
F
1/2 * 3/2 = 3/4 Three quarters is larger than 1/2
G
1/2 * 10/8 = 10/16 = 5/8 which is greater than 1/2
You can tell without doing this that when something greater than one is cut in half that the two (halves) are both equal and greater than 1/2.
H
1/2 * 5/4 = 5/8 which is greater than 1/2
The same comment as G applies here as H.
I
3/4 * 1/2 = 3/8 which is less then 4/8 which would be 1/2
Answer: I