Tính \(\int {\sin 3x\sin 2xdx} \)

A. \(\sin x + \sin 5x + C\)

B. \(\frac{1}{2}{\rm{cosx + }}\frac{1}{{10}}cos5x + C\)

C. \(\frac{1}{2}{\mathop{\rm s}\nolimits} {\rm{inx}} - \frac{1}{{10}}\sin 5x + C\)

D. \(\frac{1}{2}{\mathop{\rm s}\nolimits} {\rm{inx + }}\frac{1}{{10}}\sin 5x + C\)