A.On startup， SMON coordinates instance recovery.
B.On startup， CKPT coordinates instance recovery.
C.On startup， use RMAN to perform instance recovery.
D.Uncommitted changes will be rolled back after the database is opened.
E.On startup， perform media recovery and then instance recovery.
F.On startup， all the files will be synchronized and you get both committed and uncommitted data.

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