单选题Which statement is true regarding Flashback Version Query？ （）AIt returns versions of rows only within a transaction.BIt can be used in subqueries contained only in a SELECT statement.CIt will return an error if the undo retention time is less than the 

 It returns versions of rows only within a transaction.

 It can be used in subqueries contained only in a SELECT statement.

 It will return an error if the undo retention time is less than the lower bound time or SCN specified.

 It retrieves all versions including the deleted as well as subsequently reinserted versions of the rows.