What is the value of $$[(\cos 3\theta + 2\cos 5\theta + \cos 7\theta) \div (\cos \theta + 2\cos 3\theta + \cos 5\theta)] + \sin 2\theta \tan 3\theta$$?

A

$$\cos 2\theta$$

B

$$\sin 2\theta$$

C

$$\tan 2\theta$$

D

$$\cot \theta \sin 2\theta$$