The area of the region described by $A = \{(x, y) : x^2 + y^2 \leq 1$ and $y^2 \leq 1 - x\}$ is

Question

( A ) $\frac{\pi}{2} - \frac{4}{3}$
( B ) $\frac{\pi}{2}+ \frac{4}{3}$
( C ) $\frac{\pi}{2} - \frac{2}{3}$
( D ) $\frac{\pi}{2}+ \frac{2}{3}$