Concept:Pressure depends on the area of contact:
P=AF.
For a constant weight, pressure increases when the contact area decreases.
Explanation:The weight of the person is the same in every position.
Maximum pressure is produced when the contact area with the floor is minimum.
Lying on the floor spreads the weight over the largest area, so pressure is low.
Standing on two feet gives a larger contact area than standing on one foot.
When kneeling, the body weight is supported on the small knee area.
This area is smaller than the area of one foot.
Therefore, the pressure exerted is greatest while kneeling on the floor.
Answer:D. Kneeling on the floor.