For each (x), let (V) be the volume of the solid obtained by rotating the finite region between the curves (y = f(x)) and (y = g(x)) about the axis (x). Enter a formula for (V):
a) (V = π ∫ₐᵇ (f(x)² - g(x)²) , dx)
b) (V = π ∫ₐᵇ (f(x) + g(x))² , dx)
c) (V = π ∫ₐᵇ (f(x) - g(x))² , dx)
d) (V = π ∫ₐᵇ (g(x) - f(x))² , dx)