单项选择题

A.You should alter the default resource pool and set the MAX_CPU_PERCENT option to 80. Then assign this resource pool to the workload group used by SQL Server Management Studio. 
B.First, you should create a new resource pool and set the MAX_CPU_PERCENT option to 20. Then assign this resource pool to the workload group used by SQL Server Management Studio. 
C.You should alter the default resource pool and set the MAX_CPU_PERCENT option to 20. Then assign this resource pool to the workload group used by the mission-critical applications. 
D.First, you should create a new resource pool and set the MAX_CPU_PERCENT option to 80. Then assign this resource pool to the workload group used by the mission-critical applications.