A piston-cylinder device contains 5 kg of saturated water vapor at 3 MPa. Now heat is rejected from the cylinder at constant pressure until the water vapor completely condenses so that the cylinder contains saturated liquid at 3 MPa at the end of the process. The entropy change of the system during this process is
(a) 0 kJ/K
(b) -3.5 kJ/K
(c) -12.5 kJ/K
(d) -17.7 kJ/K
(e) -19.5 kJ/K