Which two statements are true regarding multiple-row subqueries? (Choose two.)
A.
They can contain group functions.
B.
They always contain a subquery within a subquery.
C.
They use the < ALL operator to imply less than the maximum.
D.
They can be used to retrieve multiple rows from a single table only.
E.
They should not be used with the NOT IN operator in the main query if NULL is likely to be a
part of the result of the subquery.