Examine the parameters for your database instance:
You execute the following command:
SQL> ALTER TABLESPACE undotbs1 RETENTION NOGUARANTEE;
Which statement is true in this scenario?
A.
Undo data is written to flashback logs after 1200 seconds.
B.
Inactive undo data is retained for 1200 seconds even if subsequent transactions fail due to lack of space in
the undo tablespace.
C.
You can perform a Flashback Database operation only within the duration of 1200 seconds.
D.
An attempt is made to keep inactive undo for 1200 seconds but transactions may overwrite the undo before
that time has elapsed.
Answer should be D
This question is instinct.
It should be B if asking why you need to execute this sentence; it should be D if asking what will happen after the execution.
I agree with Aritra. If RETENTION NOGUARANTEE is stated, transactions may overwrite the undo before that time has elapsed due to lack of space in the undo tablespace. D is correct.