A Spring with a Mass Of $6 \mathrm {~kg}$ Has Damping Constant 28 and Spring Constant 195

Multiple Choice

A spring with a mass of $6 \mathrm {~kg}$ has damping constant 28 and spring constant 195 . Find the damping constant that would produce critical damping.

A) $c = 6 \sqrt { 195 }$
B) $c = 6 \sqrt { 130 }$
C) $c = 780 \sqrt { 6 }$
D) $c = 24 \sqrt { 195 }$
E) $c = 195 \sqrt { 6 }$