Re: f(x) for all x?

For which of the following functions f is f(x) = f (1-x) for all x? A. f (x) = 1 - x B. f (x) = 1 - x^2 C. f (x) = x^2 - (1 - x)^2 D. f (x) = x^2 (1 - x)^2 E. f (x) = x/(1 - x)