Answer: D. White Dwarf
Explanation:
A star has life-cycle similar to any living specie. A star takes birth, goes through main sequence and dies in the end. The lifetime and the end of the star depend on the mass it holds.
A massive star turns into red super-giant and goes supernova and ends up as either a neutron star or a black-hole.
On the other hand, a small to average star like our Sun will become a red giant and throw extra mass before ending up as a white dwarf.
The color on the main sequence (blue, yellow or red) depends on the temperature and age of the star. A young hot star is blue main sequence star. On the other hand, an old low temperature star towards the end of its life is a red star.
Hence, end for a star that is small to average in size is most likely to be a D. white dwarf.
