The function f(x) is defined as follows :f(x) = (1/1-x): for x ≥ 0 and x ≠ 1 = 1 - x; otherwise and f^n (x) = f(f^(n-1) (x)) for n ≥ 2.For x = 0, find f^5(f^4(f^3(f^2(f(x))))).

1) 1
2) -1
3) 0
4) CBD