Use the Graph to Complete the Identity $\sin 6 x \cos 3 x - \cos 6 x \sin 3 x = ?$

Multiple Choice

Use the graph to complete the identity.
- $\sin 6 x \cos 3 x - \cos 6 x \sin 3 x = ?$

A) $y = \sin 3 x$
B) $y = \cos 3 x$
C) $y = \cos 9 x$
D) $y = \sin 9 x$