An SNMP alert has been generated by a server in the main data center.The alert stated that the internal temperature of the server has exceeded the threshold.No other servers in the rack have experienced problems，and no other alerts have come from that server about any other events.Which of the following is the cause of this issue？（）

• A、Rack cooling equipment failure
• B、Dust collection in the server
• C、Server processor failure
• D、Server power supply failure