I think the answer is A.
As there is brackets we need to work this out first. Let's give x a value of 1 to make it simpler.
3x1+3/4=15/4
5/4x3= 15/4.
I do apologise if I have got this wrong, this was the best I could do.
(Fun trick for remembering what comes first: BIDMAS
Brackets
Indices
Division
Multiplication
Addition
Subtraction
Hope I helped)