Direction: An ideal diatomic gas is confined in a cylinder A of volume \[{{V}_{0}},\] this cylinder is connected to another cylinder B with the help of tube of a negligible volume. The cylinder B is fitted with a movable piston which can be adjusted from outside. Initially, the piston is adjusted so that volume of B is the same as volume of A i.e., \[{{V}_{0}}\]. B is evacuated and the stopcork is opened so that gas expands and occupies the volume \[2{{V}_{0}}\]. [System is thermally isolated from the surroundings].During this free expansion, the internal energy of the system. Now with the stop-cork open, the piston is slowly moved to compress the gas back to cylinder A at temperature T. For this

• A. increases
• B. decreases
• C. remains constant
• D. nothing can be said