Determine a formula for fⁿ(x), where n is any positive integer.
A. fⁿ(x) = (-1)ⁿ⁻¹(n-1)!/xⁿ
B. fⁿ(x) = (-1)ⁿ⁻¹(n-1)!/xⁿ⁻¹
C. fⁿ(x) =(-1)ⁿ⁻¹(n-1)!xⁿ
D. fⁿ(x) =(-1)ⁿ(n-1)!/xⁿ