A particle of mass m is attached to a spring (of spring constant k) and has a natural frequency w .An external force F(t) proportional to cos w" t(w is not equal to w") is applied to the oscillator. The time displacement of the oscillator will be proportional to- (a) m/(w^2-w"^2) (b) 1/m(w^2-w"^2) (c) 1/m(w^2+w"^2) (d) m/(w^2-w"^2)