Which of the following statements is wrong? A. A main-sequence star is cooler and brighter than it was as a protostar. B. Carbon fusion occurs in high-mass stars but not in low-mass stars because the cores of low-mass stars never contain significant amounts of carbon. C. when a main-sequence star exhausts its core hydrogen fuel supply, the core shrinks while the rest of the star expands. D. After a supernova explosion, the remains of the stellar core will be either a neutron star or a black hole.

Which of the following statements is wrong? A. A main-sequence star is cooler and brighter than it was as a protostar. B. Carbon fusion occurs in high-mass stars but not in low-mass stars because the cores of low-mass stars never contain significant amounts of carbon. C. when a main-sequence star exhausts its core hydrogen fuel supply, the core shrinks while the rest of the star expands. D. After a supernova explosion, the remains of the stellar core will be either a neutron star or a black hole.