Find the derivative of f(x) where f(x) = x² - 6x - 4x⁻² + 9x⁻³.
Which of the following options represents f'(x)?
A) 2x - 6 + 8x⁻³ - 27x⁻⁴
B) 2x - 6 - 8x⁻² - 27x⁻³
C) 2x - 6 - 8x⁻² + 27x⁻³
D) 2x - 6 + 8x⁻² + 27x⁻³