Express the Sum or Difference as a Product of Sines $\sin ( 7 \theta ) + \sin ( 3 \theta )$

Multiple Choice

Express the sum or difference as a product of sines and/or cosines.
- $\sin ( 7 \theta ) + \sin ( 3 \theta )$

A) $2 \sin ( 5 \theta ) \sin ( 2 \theta )$
B) $2 \cos ( 5 \theta ) \sin ( 2 \theta )$
C) $2 \sin ( 10 \theta )$
D) $2 \sin ( 5 \theta ) \cos ( 2 \theta )$