Explanation:
The result of this setting is: a maximum of ten dispatcher threads can be active in the agent.
Incorrect Answers:
2: A maximum of ten dispatcher threads can be active in the agent, not maximum of ten sessions can be connected to the agent simultaneously.
3: This initialization parameter does not limit a maximum of concurrent sessions connected to each dispatcher.
4: Setting of MAX_DISPATCHERS parameters will not limit a maximum of external dispatcher processes can register with the listener thread.
Reference:
OCP Oracle9i Database: New Features for Administrators, Daniel Benjamin, p. 144-152
Chapter 3: Manageability Enhancements
Oracle 9i New Features, Robert Freeman, p. 59-60
Chapter 2: Oracle9i Architecture Changes

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