Perform the Indicated Operation $\frac { 14 x + 42 } { 3 x + 9 } m$

Multiple Choice

Perform the indicated operation. Simplify if possible.
-Express the perimeter of the triangle as a fully simplified rational expression.

A) $\frac { 14 x + 42 } { 3 x + 9 } m$
B) $14 \mathrm {~m}$
C) $14 \mathrm { x } + 42 \mathrm {~m}$
D) $\frac { 14 } { x + 3 } m$