An administrator is notified that a resource group has failed over from the home node， Node1 to a standbynode， Node2 and that Node1 has been powered off. Upon restarting Node1 the administrator checks the AIXerror log and the cluster.log Which of the following is the most likely cause of the failure of Node1？（）

• A、The operating system crashed
• B、A disk failure forced a volume group off line
• C、The System Resource Controller executed a system halt
• D、The topology services daemon has crashed due to an ODM mismatch