单项选择题 An administrator setting up software RAID 1 on a Windows Server with two volumes for two separate hard drives， but the option for mirrored is grayed out.  Which of the following is the MOST likely reason why this is occurring？（）

单项选择题 A user selects their proper domain and is unable to log into their Windows computer. The errorstates： System cannot log you on to the domain because the systems computer account in its primary domain is missing or the password on that account is incorrect.  Which of the following is the MOST likely cause for this error？（）

单项选择题 An administrator is troubleshooting a problem on an application server， but has not determined the cause of the problem and is not able to replicate the problem.  Which of the following should the administrator do prior to escalating the issue？（）