The equation of motion of a machine (rotating at frequency \(\omega\) ) of mass \(M\), with an unbalanced mass \(m\), at radius \(e\), is given by

a. \(m \ddot{x}+c \dot{x}+k x=m e \omega^{2} \sin \omega t\)

b. \(M \ddot{x}+c \dot{x}+k x=m e \omega^{2} \sin \omega t\)

c. \(M \ddot{x}+c \dot{x}+k x=M e \omega^{2} \sin \omega t\)