单选题You work as a database administrator for Certkiller .com. Your database is configured for automatic undo management. UNDO_RETENTION is set to 3 hours. You want to flash back a table that was created last year. How far back can the flashback query go？ （
题目
单选题
You work as a database administrator for Certkiller .com. Your database is configured for automatic undo management. UNDO_RETENTION is set to 3 hours. You want to flash back a table that was created last year. How far back can the flashback query go？ （）
A
3 hours
B
6 months
C
until last year
D
until last commit
E
until the point when the undotablespacewas refreshed
F
until the database is shut down and the memory erased