A. Solar azimuth angle
B. Zenith angle
C. Altitude angle
This question was posed to me at a job interview.
Origin of the question is Solar Constant topic in section Solar Energy of Energy Engineering
Easy explanation: The solar angle in degrees along the horizon east or west of north or it is the horizontal angle measured from north to the horizontal projection of sun’s rays is called solar azimuth angle. And it is denoted by Greek letter γs (GAMMA).