The ORACLE_SID environment variable is set to +ASM. ASMLIB Is

The ORACLE_SID environment variable is set to +ASM. ASMLIB Is not used in the configuration. 　　You executed this command to start up the Automatic Storage Management(ASM. instance: 　　SQL> STARTUP; 　　Which two activities are performed during a successful start up operation?

A.ASM discovers and examines the contents of all files in the discovery paths.

B.The disk groups are mounted.

C.The databases configured to use the ASM instance are mounted.

D.ASM starts the Oracle Cluster Synchronization Services(CSS. daemon if it is not started.

正确答案是BD