Answer: The correct answer is option D.
Explanation: Super-giant stars are the stars which are greater than Sun. They have a mass hundred time greater than Sun and can be thousand times greater than Sun.
The masses of the stars are represented in Solar masses which is the mass of the Sun.
Mass of Betelgeuse = 20 Solar masses
Mass of Pollux = 1.7 Solar masses
Mass of Sirius = 2.02 Solar masses
Mass of Sun = 1 Solar mass.
As, the mass of Sun is the least from the given stars. Hence, it is least considered as a super-giant.