In which situation would you use static database registration for a listener?
A.when multiple databases are to be registered with the listener
B.when DBAs need to connect remotely to start up the database instance
C.when users need to connect the database instance using the host naming method
D.when the database instance that is to be registered with the listener is configured in shared server mode
静态注册可以远程管理数据库，比如数据库的起停，而动态注册必须数据库启动才可以
动态注册为 ready 从字面的意思理解为准备好，而静态注册为 unknow 也就是不知道数据库状态