Write the Given Expression as the Tangent of an Angle $\frac { \tan 3 x + \tan 4 x } { 1 - \tan 3 x \tan 4 x }$

Multiple Choice

Write the given expression as the tangent of an angle. $\frac { \tan 3 x + \tan 4 x } { 1 - \tan 3 x \tan 4 x }$

A) $\tan ( 7 x )$
B) $\tan ( 3 x )$
C) $\tan ( 5 x )$
D) $\tan ( - x )$
E) $\tan ( - 5 x )$