Use the Sum-To-Product Formulas to Write the Given Expression as a Product

Multiple Choice

Use the sum-to-product formulas to write the given expression as a product. $\sin 9 \theta - \sin 7 \theta$

A) $2 \sin 8 \theta \cos \theta$
B) $2 \cos 8 \theta \cos \theta$
C) $- 2 \sin 8 \theta \sin \theta$
D) $- 2 \cos 8 \theta \cos \theta$
E) $2 \cos 8 \theta \sin \theta$