7. Which of the following statements is correct?(A) The internal energy of a system increases when more work is done by thesystem than heat was flowing into the system.(B) The internal energy of a system decreases when work is done on the systemand heat is flowing into the system.(C) The system does work on the surroundings when an ideal gas expandsagainst a constant external pressure.(D) All statements are true.(E) All statements are false.