An upright vessel has negative GM. GM becomes positive at the angle of loll because the __________.

Correct Answer: Option C — effective beam is increased causing BM to increase

As a vessel with negative initial GM heels over to an angle of loll, the shape of the waterline changes significantly. This increases the waterplane area moment of inertia, enlarging the effective beam and raising the transverse metacenter (M) above the center of gravity (G).