A Chemical Reaction Took Place in a 6 Liter Cylindrical

A chemical reaction took place in a 6 liter cylindrical enclosure fitted with a piston (like the cylinder in an internal combustion engine) . Over the time required for the reaction to be completed, the volume of the system changed from 0.400 liters to 3.20 liters. Which of the following statements below is true?

A) Work was performed on the system.
B) Work was performed by the system.
C) The internal energy of the system increased.
D) The internal energy of the system decreased.
E) The internal energy of the system remained unchanged.