Which ORDER BY clause are valid for the above query?

Evaluate the following SQL statement: SQL> SELECT cust_id, cust_last_name “Last
Name” FROM customers WHERE country_id = 10 UNION SELECT cust_id CUST_NO,
cust_last_name FROM customers WHERE country_id = 30; Which ORDER BY clause are
valid for the above query? (Choose all that apply.)

A.
ORDER BY “Last Name”

B.
ORDER BY “CUST_NO”

C.
ORDER BY 2,cust_id

D.
ORDER BY 2,1

E.
ORDER BY CUST_NO