40. The area of the region enclosed by the polar curve $r = 1 - \cos \theta$ is\\ (A) $\frac { 3 } { 4 } \pi$\\ (B) $\pi$\\ (C) $\frac { 3 } { 2 } \pi$\\ (D) $2 \pi$\\ (E) $3 \pi$\\