A: a sub query is valid on the INTO clause of an ISERT Statement
B: a sub query can be used in the FROM clause of a SELECT statement
D: a sub query can be used in the WHERE clause of a SELECT statement,
E: a sub query can be used in the SET clauses of an UPDATE statement,
Incorrect answer:
C. sub query cannot be used
F: is incorrect.
Refer: Introduction to Oracle9i: SQL, Oracle University Study Guide, 6-5