Why Does a Hot Air Balloon Rise When the Air

Multiple Choice

Why does a hot air balloon rise when the air in the balloon is heated?

A) The average kinetic energy of the air molecules increases, and the collisions between these molecules and the walls of the balloon make it rise.
B) The pressure of the gas inside the balloon increases, pushing up on the balloon.
C) The gas expands, forcing some of the gas to escape from the bottom of the balloon, and the decrease in the density of the gas lifts the balloon.
D) The balloon expands, causing it to rise.
E) The hot air rises inside the balloon, which produces enough force to lift the balloon.