In fluid mechanics, the stability of a floating body in water is significantly influenced by the relative positions of the center of gravity, center of buoyancy, and metacentre. Let's discuss these concepts in detail:

• Center of Gravity (G): It is the point where the entire weight of the floating body is considered to act. The position of the center of gravity depends on the distribution of mass within the body.
• Center of Buoyancy (B): It is the point through which the buoyant force (upward force exerted by the fluid) is considered to act. This point is the centroid of the submerged volume of the body.
• Metacentre (M): When a floating body is tilted by an external force, the vertical line passing through the center of buoyancy shifts. The metacentre is the point where this line intersects the original vertical line through the center of buoyancy when the body is upright.

A floating body is said to be in stable equilibrium if, when tilted slightly, it returns to its original position. This stability condition is determined by the relative positions of these points:

• If the metacentre (M) is above the center of gravity (G), the body will return to its original position when tilted, indicating stable equilibrium. This is because a restoring couple is generated, bringing the body back to equilibrium.
• If the metacentre is below the center of gravity, the body will continue to tilt and eventually capsize, indicating unstable equilibrium.

Therefore, the condition for stability of a floating body is that the center of gravity should be below the metacentre. This ensures that any tilt creates a righting moment that stabilizes the body.

Thus, the correct answer is that the center of gravity of the body is below the metacentre, ensuring stable equilibrium.