Explanation:
Oracle Net Manager is a graphical user interface tool that combines configuration abilities with Oracle Names component control to provide an integrated environment for configuring and managing Oracle Net. It can be used on either the client or server. Oracle Net Manager is also integrated with Oracle Enterprise Manager.
It can be used to create and configure listeners to receive client connections. Incorrect Answer:
2: Oracle Net provides the following tools to help you start, stop, configure, and control each network component: listener Control Utility, Oracle Connection Manager Control Utility, Oracle Names Control Utility.
3: Oracle Net Configuration Assistant is provided primarily to configure basic network components during installation, including listener names and protocol addresses, naming methods the client will use to resolve connect identifiers to connect descriptors, net service names in a tnsnames.ora file, directory server usage. But it can be used to create and configure listeners to receive client connections.
Reference:
OCP Oracle 9i Database: Fundamentals II Exam Guide, Rama Velpuri, p. 28-29
Chapter 2: Basic Oracle Net Architecture

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