Media recovery can sometimes be stopped by the inability to read past a certain point in the redo stream. This is often referred to as “stuck recovery”. Before Oracle9i， the Database Administrator had few options to deal with stuck recovery. If the corrupt redo could not be recovered from some other source， then all transactions that committed after the corrupt point in the redo steam would be lost. Oracle9i changes that with the Trial Recovery feature. Trial Recover is used to test the application of the redo logs to the database. What are three other characteristics of Trial Recovery（）

A. Speeds up subsequent media recover actions.
B. Writes any uncorrupted block to disk during the test recovery.
Can be invoked by adding the TEST option to any RECOVER command.
D. Allows the Administrator to determine how many blocks are affected by corruption.
E. Marks blocks as corrupt in memory， allowing the test recover to proceed to completion.