One of the user sessions was terminated abnormally in the middle of a transaction. What does Oracle database do to recover it？（）

• A、uses undo data for roll forward
• B、uses Flashback Log for recovery
• C、uses online redo logs to roll back
• D、uses undo data to roll back the transaction
• E、uses Recovery Manager （RMAN） to roll back
• F、uses the System Monitor （SMON） background process to perform instance recovery