What is the value of $$\left[ \frac{(\tan 5\theta + \tan 3\theta)}{4} \cos 4\theta (\tan 5\theta - \tan 3\theta)\right] $$?

A

$$\sin 2\theta$$

B

$$\cos 2\theta$$

C

$$\tan 4\theta$$

D

$$\cot 2\theta$$