When the height of the metacenter is the same as the height of the center of gravity of a vessel, the upright equilibrium position is __________.

Correct Answer: Option D — neutral

Equating the height of the metacenter (KM) to the center of gravity (KG) results in zero metacentric height (GM = 0). The vessel possesses neutral equilibrium, meaning it neither tends to return upright nor capsizes further when initially inclined.