单项选择题

A.GEN1/APUGEN/EXTPWRA/EXTPWRB/GEN2
B.GEN1/EXTPWRB/APUGEN/EXTPWRA/GEN2
C.GEN1/GEN2/EXTPWRA/EXTPWRB/APUGEN
D.GEN1/APUGEN/EXTPWRB/EXTPWRA/GEN2