What should be the database mode on each of the three instances for this backup to succeed?

orcl1, orcl2, and orcl3 are tnsnames that connect to predefined instances of a three-instance RAC
database which uses ASM for shared storage.
The database is in archivelog mode.

Examine the Exhibit for the tnsnames.ora entries for orcl1, orcl2, and orcl3.

You plan to execute the following RMAN commands to back up the database:
RUN{
ALLOCATE CHANNEL CH1 DEVICE TYPE DISK CONNECT ‘user1/pwd1@orcl1’;
ALLOCATE CHANNEL CH2 DEVICE TYPE DISK CONNECT ‘user2/pwd2@orcl2’;
ALLOCATE CHANNEL CH3 DEVICE TYPE DISK CONNECT ‘user3/pwd3@orcl3’;
BACKUP DATABASE PLUS ARCHIVELOG; }
What should be the database mode on each of the three instances for this backup to succeed?

A.
The database can be either mounted or open on all three instances.

B.
The database must be open on all three instances.

C.
The database must be open on any one instance and mounted on the other two instances.

D.
The database must be mounted on any one of the instances and the other instances will be
mounted automatically.

Explanation:
connectStringSpec
Purpose
Use the connectStringSpec subclause to specify the user name, password, and net service name
for connecting to a target, recovery catalog, or auxiliary database. The connection is necessary to
authenticate the user and identify the database.
Prerequisites
You must have SYSDBA privileges to CONNECT to a target or auxiliary database. Do not connect
to the recovery catalog database as user SYS.
Usage Notes
RMAN connections to a database are specified and authenticated in the same way as SQL*Plus
connections to a database. The only difference is that RMAN connections to a target or auxiliary
database require the SYSDBA privilege. The AS SYSDBA keywords are implied and cannot be
explicitly specified. See Oracle
Database Administrator’s Guide to learn about database connection options when using
SQL*Plus.
Oracle Database Backup and Recovery Reference
11g Release 2 (11.2)