relation between k,m and q

Question

1. A single degree of freedom mass-spring viscous damper system with mass m, spring constant k and viscous damping coefficient q is critically damped. The correct relation among m, k and q is    

      (a)  q=$\sqrt{2km}$                                             (b)$q=2\sqrt{km}$ 

      (c)   $q=\sqrt{\frac{2k}{m}}$                                        (d) $q=2\sqrt{\frac{k}{m}}$