Which two statements are true about the ORDER BY clause when used with a SQL statement containing a SET operator such as UNION? (Choose two.)

A: Column positions must be used in the ORDER BY clause B: Only column names from the first SELECT statement in the compound query are recognized C: The first column in the first SELECT of the compound query with the UNION operator is used by default to sort output in the absence of an ORDER BY clause D: Each SELECT statement in the compound query must have its own ORDER BY clause E: Each SELECT statement in the compound query can have its own ORDER BY clause