12. (Sichuan Province) If the curve $x^{2} \cos \alpha-y^{2} \sin \alpha$ $+2=0$ is an ellipse, then the center of the circle $(x+\cos \alpha)^{2}+(y$ $+\sin \alpha)^{2}=1$ is in ( , ).
(A) The first quadrant.
(B) The second quadrant.
(C) The third quadrant.
(D) The fourth quadrant.
$\mathrm{D}$