If we define a function f : R \ {1} R by f(x) = x² , then f is equal to (assuming the functions below are defined in the largest domain allowed by the expression)

a) g(x)= x²-1/x-1

b) g(x)= x⁴-x²/x²-1

c) g(x)= x³-x²/x-1

d) none of the above