A rope ladder with a length 1 carrying a man with a mass m at its end is attached to the basket of balloon with a mass M. The entire system if equilibrium in the air. As the man climbs up the ladder into the balloon, the balloon descend by a height h. Then the potential energy of the man

• A. increases by \[mg\]\[\left( \text{1}-\text{h} \right)\]
• B. increases b \[mgl\]
• C. increases by \[mgh\]
• D. increases by mg                                                                                                                    \[(2l-h)\]