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. $\cos 8 \theta - \cos 6 \theta$

A) $- 2 \sin 7 \theta \sin \theta$
B) $2 \cos 7 \theta \cos \theta$
C) $2 \cos 7 \theta \sin \theta$
D) $2 \sin 7 \theta \cos \theta$
E) $- 2 \cos 7 \theta \cos \theta$