Let f:R ---> R be a differentiable funtion. For all real values of x, the derivative of f(e^(2x)) with respect to x will be equal to

A. 2e^(2x) f'(x)

B. e^(2x) f'(x)

C. 2e^(2x) f'(e^2x)

D. 2f'(e^(2x))

E. f'(e^(2x))

"i put E. down but some say it is c, which is correct and y?