Which is the correct reason that propane heated air causes a hot air balloon to lift off the ground.
A. The heated air molecules turn into a solid and reduce the gravity surrounding the balloon.
B. The heated air molecules become excited and contract into a more compact formation creating lift.
C. The heated air becomes less dense than the air around it, creating lift and causing the hot air balloon to rise.
D. The heated air becomes more dense than the air around it, creating lift and causing the hot air balloon to rise.