Explanation:
Using the Oracle Shared Server architecture client-user processes ultimately connect to a dispatchers. They provide user processes with all necessary resources. Incorrect Answer:
1: They do not connect to a service.
2: Listener just helps the user process to find free or less busy dispatcher.
4: User process uses shared process resources via dispatcher.
Reference:
OCP Oracle 9i Database: Fundamentals II Exam Guide, Rama Velpuri, p. 100-102
Chapter 5: Usage and Configuration of the Oracle Shared Server

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