Consider the nonhomogeneous differential equation y" + 4y = 3x cos(2x) Which of the following represents the correct particular solution to be taken in the method of undetermined coefficients? (a) yp(x) = A cos(2x) + B sin(2x) (b) yp(x) = = x [A cos(2x) + B sin(2x)] + C cos(2x) + D sin(2x) (c) yp(x) = x² [A cos(2x) + B sin(2x)] + x [C cos(2x) + D sin(2x)] (d) yp(x) = x² [A cos(2x) + B sin(2x)]+x [C cos(2x) + D sin(2x)] + E cos(2x)+F sin(2x)