Which function is the inverse of F(x) = b^x?
AF-1(y) = logby
BF-1(y) = logxb
CF-1(y) = logxy
DF-1(y) = logyb
AF-1(y) = logby
BF-1(y) = logxb
CF-1(y) = logxy
DF-1(y) = logyb