When a body is completely or partially immersed in a fluid, its weight is distributed in such a way that it achieves stable equilibrium. In this case, the correct answer is option 'A', which states that the weight is distributed around the lower part of the body.

Explanation:

1. Stable Equilibrium:
Stable equilibrium refers to a state where an object remains at rest even when slightly disturbed. In the case of a body immersed in a fluid, stable equilibrium is achieved when the weight is distributed in a specific manner.

2. Buoyant Force:
When a body is immersed in a fluid, it experiences an upward force called the buoyant force. This force is equal to the weight of the fluid displaced by the body, according to Archimedes' principle.

3. Center of Buoyancy:
The buoyant force acts vertically upward through a point called the center of buoyancy. This point represents the centroid of the fluid volume displaced by the body.

4. Center of Gravity:
The weight of the body acts vertically downward through a point called the center of gravity. This point represents the centroid of the body.

5. Stable Equilibrium Condition:
For stable equilibrium, the center of gravity of the body must be below the center of buoyancy. This ensures that any slight disturbance will cause the body to return to its original position.

6. Weight Distribution:
To achieve stable equilibrium, the weight of the body must be distributed around the lower part. This means that the center of gravity must be located below the center of buoyancy.

7. Importance of Weight Distribution:
If the weight distribution is not around the lower part, the body will not achieve stable equilibrium. For example, if the weight is distributed around the upper part, even a slight disturbance will cause the body to topple over.

In conclusion, when a body is completely or partially immersed in a fluid, its weight must be distributed around the lower part for it to be in stable equilibrium. This ensures that the center of gravity is below the center of buoyancy, allowing the body to return to its original position when slightly disturbed.