If $$\alpha $$, H, A and $$\delta $$ be the altitude, hour angle, azimuth and declination of a circumpolar star at its elongation, in latitude $$\lambda $$, the following relation holds good

A. $$\cos {\text{H}} = \frac{{\tan \lambda }}{{\tan \delta }}$$

B. $$\sin \alpha = \frac{{\sin \lambda }}{{\sin \delta }}$$

C. $$\sin {\text{A}} = \frac{{\cos \delta }}{{\cos \lambda }}$$

D. All the above

Answer: Option D