170 kJ of heat is supplied to a system at constant volume. Then the system rejects 180 kJ of heat at constant pressure and 40 kJ of work is done on it. The system is finally brought to its original state by adiabatic process. If the initial value of internal energy is 100 kJ, then which one of the following statements is correct?
a. The. highest value of internal energy occurs at the end of the constant volume process
b. The highest value of internal energy occurs at the end of constant pressure process
c. The highest value of internal energy occurs after adiabatic expansion
d. Internal energy is equal at all points