Use the Sum-To-Product Formulas to Rewrite the Sum or Difference $$\sin 3 \theta - \sin \theta$$

Multiple Choice

Use the sum-to-product formulas to rewrite the sum or difference as a product.​ $$\sin 3 \theta - \sin \theta$$ ​

A) ​ $2 \sin 3 \theta \cos \theta$
B) ​ $2 \sin 2 \theta \cos \theta$
C) ​ $2 \cos 2 \theta \cos \theta$
D) ​ $2 \sin 2 \theta \sin \theta$
E) ​ $2 \cos 2 \theta \sin \theta$