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

- $q=\sqrt{2km} \\$
- $q=2\sqrt{km} \\$
- $q=\sqrt{\dfrac{2k}{m}} \\$
- $q=2\sqrt{\dfrac{k}{m}}$