If a wooden block is placed in three different positions on a floor, which position of the block will exert the greatest force on the floor?

Whatever be the position of the block on the floor the force by the block on the floor will remain same and is equal to the weight of the block. The pressure exerted by the block on the floor will vary according to the area of contact between the block and the floor. When the area of contact is small the pressure is large and when the area of contact is large the pressure is small.