You work in a company which is named Wiikigo Corp. The company uses SQL Server 2008. You are the administrator of the company database. Now you are in charge of a SQL Server 2008 instance. There is a database named DB1 in the instance. DB1 is available to a Windows group which is named WIIKIGO/Supervisors. A Windows user named User1 is a member of the WIIKIGO/Supervisors group. WIIKIGO/Supervisors is a member of the db_owner role in the DB1 database. You must make sure that the SQL Server instance is available to User1. In the DB1 database, which Transact-SQL statement(s) should you execute?（）  

• A、 DROP LOGIN "WIIKIGO/User1"; 
• B、 EXEC dbo.sp_droprolemember 'db_owner', 'WIIKIGO/User1';
• C、 EXEC dbo.sp_revokedbaccess 'WIIKIGO/User1';EXEC dbo.sp_revokelogin 'WIIKIGO/User1'; 
• D、 CREATE LOGIN "WIIKIGO/User1" FROM Windows;DENY CONNECT SQL TO "WIIKIGO/User1";