In the Process of Helium Shell Fusion in a Low-Mass

In the process of helium shell fusion in a low-mass star near the end of its life, the star moves upward and to the right on the asymptotic giant branch of the Hertzsprung-Russell diagram. In this process, the star is

A) contracting, cooling, and hence becoming less luminous.
B) expanding, heating up, and becoming more luminous.
C) contracting, becoming hotter, and becoming much less luminous.
D) expanding, cooling, and becoming more luminous.