Evaluate the Integral $\int 3 \sin 5 x \sin 2 x d x$

Multiple Choice

Evaluate the integral.
- $\int 3 \sin 5 x \sin 2 x d x$

A) $3 \left( \frac { \cos 3 x } { 6 } - \frac { \cos 7 x } { 14 } \right) + C$
B) $3 \left( \frac { \sin 3 x } { 6 } - \frac { \sin 7 x } { 14 } \right) + C$
C) $3 \left( \frac { \sin 3 x } { 6 } + \frac { \sin 7 x } { 14 } \right) + C$
D) $3 ( \sin 3 x - \sin 7 x ) + C$