When floating a ping-pong ball with a hairdryer, which two forces are balanced? Force pushing up:
Force pulling down:

The ping-pong ball will fly up with the air from the hair dryer until it reaches a point of balance – this is where the force of gravity (which pushes the ping-pong ball down) is equal to the force of the air (which is pushing the ping-pong ball up).

option number c is the right answer.