Answer:
C. Pulley
Explanation:
A pulley is a simple machine used to raise an object against the gravitational force. It can be used to lift heavy things as well.
When we raise a flag, a pulley is attached at the top of the rod/pillar. Through that pulley a rope is attached along with flag. As the rope is dragged downwards, the flag lifts up.
Same theory is applied while taking water out from a well.
