39.The Advanced Turbogenerator System (ATG) extracts the heat energy from the exhaust of
propulsion plant and converts this residual heat to electrical power. What are the machineries in the ATG system?①auxiliary boiler ②diesel engine ③exhaust gas economizer ④steam turbine engine
(A)①②③
(B)②③④
(C)③④①
(D)④①②