Explanation:

Introduction to Inclined Plane:
An inclined plane is a flat supporting surface tilted at an angle. It is used to make it easier to lift or lower objects by reducing the amount of force required. The inclined plane allows objects to be moved along a slope rather than lifting them vertically.

Understanding Total Pressure:
Total pressure on an inclined plane is the sum of the normal force (perpendicular to the plane) and the gravitational force (acting vertically downward).

Explanation:
The correct answer is option 'B' - Vertical.

Reason:
When an inclined plane is vertical, the normal force acting on it is equal to the weight of the object placed on it. This is because the inclined plane is perpendicular to the vertical direction.

Key Points:
- The normal force is the force exerted by a surface to support the weight of an object resting on it.
- In the case of an inclined plane, the normal force is perpendicular to the surface of the plane.
- When the inclined plane is vertical, the normal force is equal to the weight of the object.
- The weight of an object is the force exerted on it due to gravity and is always directed vertically downward.
- Therefore, when the inclined plane is vertical, the maximum total pressure acts on it because the normal force is at its maximum value.
- In contrast, when the inclined plane is horizontal or inclined at an angle, the normal force is less than the weight of the object, resulting in a lower total pressure.

Conclusion:
The maximum total pressure acts on a vertical inclined plane because the normal force is equal to the weight of the object.