The correct answer is: C. center of buoyancy
The center of buoyancy is the point at which the buoyant force acts on an object. It is located directly below the center of gravity of the displaced fluid.
The center of pressure is the point at which the total pressure of a fluid acts on an object. It is located at the centroid of the wetted surface of the object.
The metacenter is the point of intersection between the vertical line through the center of buoyancy and the vertical line through the center of gravity of an object. It is important in determining the stability of a floating object.
The center of gravity is the point at which the entire weight of an object can be considered to be concentrated. It is located at the average position of the mass of the object.