A balloon of mass M is floating motionless in the air. A person of mass less than M is on a rope ladder hanging from the balloon. The person begins to climb the ladder at a uniform speed v relative to the ground. How does the balloon move relative to the ground?

1. Up with a speed less than v
2. Down with a speed less than v
3. The balloon does not move
4. Down with speed v
5. Up with speed v