The reversible expansion of an ideal gas under adiabatic and isothermal conditions is shown in the figure. Which of the following statement(s) is (are) correct?
A. `T_(1)=T_(2)`
B. `T_(3)gt T_(1)`
C. `W_(isothemal) gt W_(adiabatic)`
D. `DeltaU_(isothemal) gt DeltaU_(adiabatic)`