备用电源系统（ABEX,HMG,SEP)向什么汇流条供电？

AEssential DC bus(Using the TRU)

BEssential AC bus(Using the E-inverter)

CEssential DC bus(Using the TRU)和Essential AC bus(Using the E-inverter)

DEssential DC bus(Using the E-inverter)和Essential AC bus(Using the TRU)