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

Correct Answer: Option B — original vertical centerline

Stability principles dictate that when a vessel heels due to external forces, the center of gravity remains fixed relative to the ship's structure. In the absence of external forces, the center of gravity must align vertically with the center of buoyancy, which lies on the original vertical centerline.