Answer:
B
Step-by-step explanation:
Myself, I'd pick B. It is uncluttered by unnecessary brackets and reduced to its final answer, but that does not mean I am correct. A is correct as well 6ad = 6a*d. C is also correct for the same reason. D is incorrect and incomplete. E is a nightmare.
I'd pick B but don't be surprised if it is A or C.
