Use the Sum-To-Product Formulas to Rewrite the Sum or Difference $\sin 9 \theta + \sin 7 \theta$

Multiple Choice

Use the sum-to-product formulas to rewrite the sum or difference as a product. $\sin 9 \theta + \sin 7 \theta$

A) $2 \sin 8 \theta \sin \theta$
B) $2 \cos 8 \theta \cos \theta$
C) $2 \sin 8 \theta \cos \theta$
D) $2 \cos 8 \theta \sin \theta$
E) $2 \sin 9 \theta \cos 7 \theta$