Answer:
The first option is correct.
Heat energy was removed from the air in the balloon.
The air in the balloon did work on the atmosphere.
Explanation:
When the pressure is constant V/T is constant for a gas.
So 1000/ 293 = V / 283 (where the temperature is in degrees K.)
So the volume will decrease from 1000 cm^3.
Also as the temperature outside is colder the air in the balloon lost energy.