# Express the following as the sum difference of cosines and sines $2\sin 3\theta.\cos\theta$
$\begin{array}{1 1}(A)\;\sin 4\theta+\sin 2\theta\\(B)\;\sin 3\theta+\sin 3\theta\\(C)\;\sin \theta+\cos 2\theta\\(D)\;\text{None of these}\end{array}$