Which statement is true regarding Flashback Version Query？（）

• A、 It returns versions of rows only within a transaction.
• B、 It can be used in subqueries contained only in a SELECT statement.
• C、 It will return an error if the undo retention time is less than the lower bound time or SCN specified.
• D、 It retrieves all versions including the deleted as well as subsequently reinserted versions of the rows.