A Star Ascending the Red-Giant Branch for the Second Time

Multiple Choice

A star ascending the red-giant branch for the second time in the asymptotic giant branch (AGB) phase will have

A) no nuclear reactions in the core, but a helium-fusion shell outside the core, which itself is surrounded by a shell of hydrogen.
B) no fusion reactions; the star has used up all its nuclear fuel.
C) hydrogen-fusion reactions occurring in the core.
D) no nuclear reactions occurring in the core but hydrogen fusion in a shell outside the core.