$$\displaystyle\int_{-3\pi/2}^{-\pi/2}\left[(x + \pi)^3 + \cos^2(x + 3\pi)\right]dx$$ is equal to

A

$$\dfrac{\pi^4}{32}$$

B

$$\dfrac{\pi^4}{32} + \dfrac{\pi}{2}$$

C

$$\dfrac{\pi}{2}$$

D

$$\dfrac{\pi}{4} - 1$$