$\text { Find } \int \sin 5 x \cos 10 x d x \text {. }$

Multiple Choice

$\text { Find } \int \sin 5 x \cos 10 x d x \text {. }$

A) $\int \sin 5 x \cos 10 x d x = \frac { 1 } { 30 } ( 3 \cos 5 x - \cos 15 x ) + C$
B) $\int \sin 5 x \cos 10 x d x = \frac { 1 } { 15 } ( 3 \cos 14 x + 3 \cos 5 x ) + C$
C) $\int \sin 5 x \cos 10 x d x = \frac { 1 } { 31 } ( \cos 15 x - 3 \cos 5 x ) + C$
D) $\int \sin 5 x \cos 10 x d x = \frac { 1 } { 30 } ( 4 \cos 5 x + \cos 14 x ) + C$
E) $\int \sin 5 x \cos 10 x d x = \frac { 1 } { 31 } ( 3 \cos 5 x - \cos 15 x ) + C$