I believe it’s c ^^
since you multiply the numerators and denominators.. so since the first fraction is 1/2 & the second is 3/4, you’d multiply it like:
1 x 3 & 2 x 4, giving you 3/8.
        
             
        
        
        
If you take the amount of green markers and divide them by the total, you come up with 0.21
If you do likewise with the others, you respectively come up with 0.47 and 0.32.