Explanation:
You should use roles to grant a group of privileges to a user. You grant the appropriate privileges to the role and after that grant this role to specific users. By granting to or revoking privileges from the role you can simplify procedure of users privileges maintainance: you don’t need to grant/revoke privileges to/from each user. It’s especially very helpful when you are experiencing a high number of people using the database.
Incorrect Answers:
1: Roles have nothing to do with simplifying the process of creating new users.
2: You can use roles to grant a group of privileges to a user, but they can be not related at all.
5: Roles have nothing to do with user who is constantly traveling.
OCP Introduction to Oracle 9i: SQL Exam Guide, Jason Couchman, p. 365-372
Chapter 8: User Control in Oracle

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