The current time zone for one of the user sessions is set to the database local time zone. For one application， the user session requires the time zone to be set to the local operating system time zone without affecting other user sessions. Which two solutions could the user implement to achieve this objective？ （）
A、 use the ALTER SYSTEM command to change the time zone
B、 use the ALTER SESSION command to change the time zone
C、 use the ALTER DATABASE command to change the time zone
D、 set the value for the operating system variable ORA_SDTZ on the client machine
E、 set the value for the operating system variable ORA_SDTZ on the database server machine
