Which statement is true about Oracle Net Listener?（）

A. It acts as the listening endpoint for the Oracle database instance for all local and non-local user connections.
B. A single listener can service only one database instance and multiple remote client connections.
C. Service registration with the listener is performed by the process monitor (PMON) process of each database instance.
D. The listener.ora configuration file must be configured with one or more listening protocol addresses to allow remote users to connect to a database instance.