Which of the following is not one of the three ways to express ratio a 3/4 b 3: 4 c 3 of 4 d 3 to 4

C. 3 of 4
Hope this helps :)

Ratios are written like 1:2, 3:4, 100:200 i.e. with a colon
Ratios can be described with words that can replace the colon
i.e. 1 to 2, 1 of 2 etc.

Personally, i'd say all of them are acceptable, but the answer must be 
A: 3/4, since that is surely a fraction

I’m not sure i’m sorry