52题、choose one
When is the UNDO_RETENTION parameter value ignored by a transaction?
A) when Flashback Database is enabled
B) when the undo tablespace is of a fixed size and retention guarantee is not enabled
C) when there are multiple undo tablespaces available in a database
D) when the data file of the undo tablespace is autoextensible
Answer：A
(解析：启用闪回数据库时，对undo_retention这个参数是没有任何关系，其它的答案都跟这个参数相关。来自3组：1015267481)