Explanation:
To look on the view definition you need to query the USER_VIEWS data dictionary view and search for the EMP_DEPT_VU view.
Incorrect Answers:
1: You cannot see the definition of the view using the DESCRIBE command.
2: There is no DEFINE VIEW command in Oracle.
3: There is no DESCRIBE VIEW command in Oracle.
5: You cannot use the USER_SOURCE data dictionary view to see the definition of your view: it is used to store system objects definitions only.
6: You can find record about view in the USER_OBJECTS, but it does not contain the definition of the view itself.
OCP Introduction to Oracle 9i: SQL Exam Guide, Jason Couchman, p. 291-301
Chapter 7: Creating Other Database Objects in Oracle

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