If $(2+\sin x) \frac{dy}{dx} +(y+1) \cos x = 0$ and $y(0)=1$, then $y(\frac{\pi}{2})$ is equal to :

Question

( A ) $\frac{1}{3}$
( B ) $-\frac{2}{3}$
( C ) $-\frac{1}{3}$
( D ) $\frac{4}{3}$