How will the gravitational force on a piece of the surface of the star (m1) by the mass of the rest of the star (m2) (effectively located at a point at the center of the star) compare between the AGB and main-sequence phases of a particular star, assuming its mass stays the same?A. The surface will feel a stronger gravitational force during the AGB phase because the star is larger.
B. The surface will feel a weaker gravitational force during the AGB phase because it is farther from the center of the star.
C. The surface will feel the same gravitational force during both phases.