What are the default connect strings used by SQL*Plus and ASMCMD when connecting to ASM instances?

What are the default connect strings used by SQL*Plus and ASMCMD when connecting to ASM
instances?

A.
operating system authentication for ASMCMD;
none for SQL*Plus

B.
“/ AS SYSASM” for ASMCMD;
“/” for SQL*Plus

C.
“SYS/ AS SYSASM” for ASMCMD;
“/ AS SYSDBA” for SQL*Pius

D.
operating system authentication for ASMCMD;
operating system authentication for SQL*Plus

E.
“/ AS SYSASM” for ASMCMD;
operating system authentication for SQL*Plus

Explanation:
On Linux and UNIX systems, dba is the default operating system group designated
as OSASM, OSOPER, and OSDBA for Oracle ASM. On Windows systems, ora_dba is the default
name designated as OSASM, OSOPER, and OSDBA.
SQL*Plus commands, ASMCMD commands, and ASMCA use operating system authentication
To connect locally as SYSASM to an Oracle ASM instance using operating system authentication
with SQL*Plus, use the following statement:
sqlplus / AS SYSASM

OSASM group
This group is granted the SYSASM privilege, which provides full administrative privileges for the
Oracle ASM instance.
You can specify the –privilege option to choose the type of connection, either SYSASM or
SYSDBA. The default value is SYSASM and is used when administering an Oracle ASM instance.
Connect as SYSDBA when connecting to the database instance.
For example:
$ asmcmd –privilege sysasm
usage: asmcmd [-V] [-v <errors|warnings|normal|info|debug>] [–privilege <sysasm|sysdba>] [-p]
[command]