If fff\(\frac{8^r}{4^s}=2^t\)/fff, then what is r in terms of s and t ?
A.s + t + 1
B.s + t + 5
C.fff\(\frac{(2s+t)}{3}\)/fff
D.fff\(\frac{2st}{3}\)/fff
E.fff\((\frac{s}{2})+(\frac{t}{4})\)/fff
我的答案：
