Your company has a main office and a branch office. The network contains an Active Directory  domain.  
The main office contains a writable domain controller named DC1. The branch office contains a  read- only domain controller （RODC） named DC2.  
You discover that the password of an administrator named Admin1 is cached on DC2.    
You need to prevent Admin1’s password from being cached on DC2.    
What should you do（）

Your network contains an Active Directory domain. The domain contains two sites named Site1  and Site2. Site1 contains four domain controllers. Site2 contains a read-only domain controller  （RODC）. You add a user named User1 to the Allowed RODC Password Replication Group. The  WAN link between Site1 and Site2 fails.    
User1 restarts his computer and reports that he is unable to log on to the domain. The WAN link  is restored and User1 reports that he is able to log on to the domain. You need to prevent the  problem from reoccurring if the WAN link fails.    
What should you do（）