ATS机柜如需关机时，开关机顺序正确的是
A关机时：先关主机电源，然后关机柜空开；开机时：先开主机电源，再开机柜空开
B关机时：先关机柜空开，然后关主机电源；开机时：先开主机电源，再开机柜空开
C关机时：先关主机电源，然后关机柜空开；开机时：先开机柜空开，再开主机电源
D关机时：先关机柜空开，然后关主机电源；开机时：先开机柜空开，再主机电源
A关机时：先关主机电源，然后关机柜空开；开机时：先开主机电源，再开机柜空开
B关机时：先关机柜空开，然后关主机电源；开机时：先开主机电源，再开机柜空开
C关机时：先关主机电源，然后关机柜空开；开机时：先开机柜空开，再开主机电源
D关机时：先关机柜空开，然后关主机电源；开机时：先开机柜空开，再主机电源