Final answer:
A brown dwarf could be described as ‘almost, but not quite a star’A brown dwarf is an object intermediate in size between a planet and a star. It is capable of deuterium fusion but not hot enough to fuse protons and become a true star.
Step-by-step explanation:
A brown dwarf could be described as ‘almost, but not quite a star’. It is an object intermediate in size between a planet and a star. Brown dwarfs have a mass range from about 1/100 of the mass of the Sun up to the lower mass limit for self-sustaining nuclear reactions, which is about 0.075 the mass of the Sun. While brown dwarfs are capable of deuterium fusion, they are not hot enough to fuse protons and become true stars. Therefore, the correct answer is b. Brown dwarf.