simplify!

r^2s^5t^4 over (like a fraction) r^2s^2t^5

A. S^3 over t^2

B. S^3 over t

C. S^2 over t^3

D. S over t

** a letter with -- ^ means to that power**

thank you!

r^2s^5t^4 / r^2s^2t^5 = s^3/t