Answer: A, B, D
Adiabatic means q=0, so ΔU=w; a reversible adiabatic path has ΔS=qrev/T=0. The gas does work at the expense of internal energy, so T falls. In the isothermal case T stays constant, the pressure stays higher along the path, and more work is done; hence the statement about smaller work than the isothermal case is true and the statement that the final temperature is unchanged is false.