The correct answer is D. All the above.
The altitude $\alpha$ is the angle between the horizon and the star. The hour angle $H$ is the angle between the star and the meridian, measured eastward from the observer’s meridian. The azimuth $A$ is the angle between the observer’s north point and the line of sight to the star, measured eastward from north. The declination $\delta$ is the angle between the star’s celestial equator and the observer’s celestial equator.
The following diagram shows the relationship between these angles:
[Diagram of a circumpolar star at its elongation]
The star is at its elongation when it is at its maximum angular distance from the observer’s north celestial pole. This occurs when the hour angle is $90^\circ$ minus the observer’s latitude $\lambda$.
The altitude of the star at its elongation is given by
$$\alpha = \arctan \left( \frac{\sin \delta}{\sin \lambda} \right)$$
The hour angle of the star at its elongation is given by
$$H = 90^\circ – \lambda$$
The azimuth of the star at its elongation is given by
$$A = \arctan \left( \frac{\cos \delta}{\cos \lambda} \right)$$
Therefore, the following relations hold good:
$$\cos H = \frac{\tan \lambda}{\tan \delta}$$
$$\sin \alpha = \frac{\sin \lambda}{\sin \delta}$$
$$\sin A = \frac{\cos \delta}{\cos \lambda}$$