The value of the integral $$\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}\left(x^2 + \ln \frac{\pi + x}{\pi - x}\right)\cos x dx$$ is

A

0

B

$$\frac{\pi^2}{2} - 4$$

C

$$\frac{\pi^2}{2} + 4$$

D

$$\frac{\pi^2}{2}$$