A Spring with a Mass Of $9 \mathrm {~kg}$ Has Damping Constant 28 and Spring Constant 192

Multiple Choice

A spring with a mass of $9 \mathrm {~kg}$ has damping constant 28 and spring constant 192 . Find the damping constant that would produce critical damping.

A) $c = 288 \sqrt { 3 }$
B) $c = 48 \sqrt { 3 }$
C) $c = 2304$
D) $c = 9 \sqrt { 192 }$
E) $c = 192 \sqrt { 9 }$