OCP 1Z0 052 133

133. Your database is open and the LISTENER listener is running. The new DBA of the system stops the 
listener by using the command: 
LSNRCTL> STOP  
What happens to the sessions that are presently connected to the database instance?  
A.The sessions are able to perform only queries. 
B.The sessions are not affected and continue to function normally. 
C.The sessions are terminated and the active transactions are rolled back. 
D.The sessions are not allowed to perform any operations till the listener is started. 
Answer: B

listener 就是个牵线拱桥的，已接上头的不受影响。