Solve the given differential equation by undetermined coefficients: (y'' - 4y = (x² - 9) sin(2x)).
a) (y = Ax² + Bx + C)
b) (y = (Ax² + Bx + C) sin(2x) + (Dx² + Ex + F) cos(2x))
c) (y = (Ax² + Bx + C) sin(2x))
d) (y = (Ax² + Bx + C) cos(2x) + (Dx² + Ex + F) sin(2x))