Which two statements about sub queries are true? (Choose two.)
A.
A sub query should retrieve only one row.
B.
A sub query can retrieve zero or more rows.
C.
A sub query can be used only in SQL query statements.
D.
Sub queries CANNOT be nested by more than two levels.
E.
A sub query CANNOT be used in an SQL query statement that uses group functions.
F.
When a sub query is used with an inequality comparison operator in the outer SQL
statement, the column list in the SELECT clause of the sub query should contain only one
column.