Let f: x>x such that f(f(x)) = x for all xex. then (a) f is one-to-one and onto (a) b) fis one-to-one, but not onto (c) f is onto but not one-to-one (d) need no

Let f: X>X such that f(f(x)) = x for all xeX. Then (a) f is one-to-one and onto (a) b) fis one-to-one, but not onto (c) f is onto but not one-to-one (d) need not be either one-to-one or onto