Your database instance is running. You are not able to access Oracle Enterprise Manager Database Control because the listener is not started.
Which tool or utility would you use to start the listener?
A. Oracle Net Manager
B. Listener Control utility
C. Database Configuration Assistant
D. Oracle Net Configuration Assistant
A.D 工具是用来配置网络服务的，但是启动和关闭不能操作。 C 是数据库配置工具。只有监听控制工具能启动和关闭监听，B 对
此处 Listener Control utility 即我们常用的 lsnrctl 工具。