When Sliding a Heavy Box Across the Floor, It Is

Multiple Choice

When sliding a heavy box across the floor, it is often times helpful to lift up on it slightly because

A) You are lessening the friction force by reducing the contact force between the box and the floor
B) You are reducing the weight of the box.
C) You are working against friction by lifting up.
D) You are working against gravity, even if the box does not move upwards.