What is the value of $$\left\{\frac{[\sin (x + y) - 2 \sin x + \sin (x - y)]}{[\cos (x - y) + \cos (x + y) - 2 \cos x]}\right\} \times \left[\frac{(\sin 10x - \sin 8x)}{(\cos 10x + \cos 8x)}\right]$$?

A

0

B

$$\tan^2 x$$

C

1

D

$$2 \tan x$$