Which expression is equivalent to the expression shown?

3 to the power of 7 x 3 to the power of -4

A. 3 to the power of 7 x 1/3 (The three in 1/3 is to the power of 4)

B. 3 to the power of 7 x 1/3 (The three in 1/3 is to the power of -4)

C. 3 to the power of -28

D. 3 to the power of 7 x (-3) times the power of 4

Idk, think it's A and please explain why because I don't understand.
Nvm I got the answer. But thanks if you tried to answer!