A vehicle suspension system consists of a leaf spring and a damper. The stiffness of the leaf spring is 3.6 KN/m and damping constant of the damper is 400 Ns/m. If the mass is 50Kg, then the damping factor and damped natural frequency respectively are

A

0.471 and 1.19 Hz

B

0.471 and 7.48 Hz

C

0.666 and 1.35 Hz

D

0.666 and 8.50 Hz