A hyperbola, having the transverse axis of length $2\sin\theta$, is confocal with the ellipse $3x^2 + 4y^2 = 12$. Then its equation is\\
(A) $x^2\csc^2\theta - y^2\sec^2\theta = 1$\\
(B) $x^2\sec^2\theta - y^2\csc^2\theta = 1$\\
(C) $x^2\sin^2\theta - y^2\cos^2\theta = 1$\\
(D) $x^2\cos^2\theta - y^2\sin^2\theta = 1$