With no environmental forces acting on the vessel, the center of gravity of an inclined vessel is vertically aligned with the __________.

Correct Answer: Option A — original vertical centerline

In the absence of external forces, the center of gravity and the center of buoyancy must lie on the same vertical line. For an inclined vessel, this line passes through the original vertical centerline, maintaining the equilibrium of the vessel's internal forces relative to the center of gravity.