The correct answer is - b. Blue.
The color of the stars can tell us multiple things about its properties, and of them is the temperature of the star. The stars that have blue color are the stars that have the highest temperatures of 33,000 K or more.
After the blue ones, come the blue to blue white, then the white, yellowish white, yellow, orange, and last are the red with temperatures of 3,700 K or less.
The temperatures of the stars depend on their age, and in which faze of their evolution are they, so the younger stars tend to be hotter, while the ones that are in dying faze are the coolest.
