Which statement is correct regarding the operation of DHCP?（）

• A、A DHCP client uses a ping to detect address conflicts.
• B、A DHCP server uses a gratuitous ARP to detect DHCP clients.
• C、A DHCP client uses a gratuitous ARP to detect a DHCP server.
• D、If an address conflict is detected, the address is removed from the pool and an administrator must resolve the conflict.
• E、If an address conflict is detected, the address removed from the pool for an amount of time configurable by the administrator.
• F、If an address conflict is detected, the address is removed from the pool and will not be reused until server is rebooted.