What is correct about the power supply specification is:
选项：

A:
A: A regulated power supply (such as UPS) shall be used to filter the fluctuation of the power grid and provide stable voltage and current for the equipment.
B:
B: AC power socket for equipment power supply shall be single-phase three-wire power socket with protective earth wire (PE), and the protective earth wire (PE) shall be reliably grounded.
C:
C: Ensure that the independent equipment is connected to the independent power distribution protection device, one power module is connected to one power line, and the power lines of the dual redundant equipment are cross-connected to ensure the redundancy of the power supply.
D:
D: As the UPS is not in place, the equipment can be powered up by the mains supply first, and then shut down after the commissioning is completed, and disconnect the mains supply.