Complete the Identity $$\frac { \sin 3 x + \sin 7 x } { \cos 3 x + \cos 7 x } = ?$$

Multiple Choice

Complete the identity.
- $$\frac { \sin 3 x + \sin 7 x } { \cos 3 x + \cos 7 x } = ?$$

A) $\tan 5 x$
B) $\tan 3 x + \tan 7 x$
C) $2 \tan 5 x \tan 2 x$
D) $\tan 5 x \cot 2 x$