You are the Database Administrator （DBA） of your company. You execute the following statement on an Oracle 10g instance：   SQL> ALTER SYSTEM SWITCH LOGFILE；   Which two tasks are performed when the statement is executed？ （）

• A、 The DBWn process writes to the datafile.
• B、 Changes in the background process are recorded.
• C、 The log file is updated with the current SCN number.
• D、 The System Change Number （SCN） is recorded in the control file.
• E、 The changes to the listener configuration in the listener.ora file are recorded.