A star at the end of its life-cycle, composed of mostly carbon, is a

A. nova.

B. giant.

C. red dwarf.

D. white dwarf.

A star at the end of it's life cycle is called a white dwarf (answer D). The order of life in the answer choices given is giant, red dwarf, white dwarf and nova. The nova, while the final stage is actually the explosive death of a star. The white dwarf state is a small, hot star that is that is dense in composition and composed of mostly carbon and oxygen.