Simplify by Combining Like Radicals $\sqrt { 216 m } - \sqrt { 192 m } + \sqrt { 588 m }$

Multiple Choice

Simplify by combining like radicals. The variable represents a positive real number. $\sqrt { 216 m } - \sqrt { 192 m } + \sqrt { 588 m }$

A) $6 \sqrt { 6 m } + 6 \sqrt { 3 m }$
B) $14 \sqrt { 6 m } + 6 \sqrt { 3 m }$
C) $6 \sqrt { 6 m } + 14 \sqrt { 3 m }$
D) $14 \sqrt { 6 m } - 6 \sqrt { 3 m }$
E) $6 \sqrt { 6 m } - 6 \sqrt { 3 m }$