Which three statements are true regarding subqueries?

Which three statements are true regarding subqueries?

A.
Multiple columns or expressions can be compared between the main query and subquery.

B.
Subqueries can contain ORDER BY but not the GROUP BY clause.

C.
Main query and subquery can get data from different tables.

D.
Subqueries can contain GROUP BY and ORDER BY clauses.

E.
Main query and subquery must get data from the same tables.

F.
Only one column or expression can be compared between the main query and subquery.

Explanation:
http://docs.oracle.com/javadb/10.6.2.1/ref/rrefsqlj13658.html