Which statement is true about the outcome?

In your database, the flash recovery area (FRA) is configured as the default for RMAN backups. You executed the following commands to configure the settings in RMAN:

RMAN> CONFIGURE DEVICE TYPE disk PARALLELISM 2 BACKUP TYPE TO BACKUPSET;
RMAN> CONFIGURE CHANNEL 1 DEVICE TYPE disk FORMAT ‘/home/oracle/disk1/%U’;
RMAN> CONFIGURE CHANNEL 2 DEVICE TYPE disk FORMAT ‘/home/oracle/disk2/%U’;

You issue the following RMAN command to backup the database:

RMAN> RUN
2> {
3> ALLOCATE CHANNEL ch1 DEVICE TYPE disk;
4> BACKUP DATABASE;
5> }

Which statement is true about the outcome?

A.
Only one channel is allocated and the backup is created in the flash recovery area

B.
Only one channel is allocated and the backup is created in the destination specified for channel 1

C.
Two channels are allocated and backup sets are created in the destinations specified for channels 1 and 2

D.
Three channels are allocated and backup sets are created in the destinations specified for channels 1, 2, and FRA

Explanation:
http://download.oracle.com/docs/cd/B19306_01/backup.102/b14192/setup004.htm#i1017890
Configuring Disk Devices and Channels:

RMAN channels (connections to server sessions on the target database) perform all RMAN tasks. By default, RMAN allocates one disk channel for all operations.

The following command configures RMAN to write disk backups to the /backup directory (refer to “Backing Up Database Files and Archived Logs with RMAN”).:

CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT ‘/backup/ora_df%t_s%s_s%p’;

The format specifier %t is replaced with a four byte time stamp, %s with the backup set number, and %p with the backup piece number.

You can also configure an Automatic Storage Management disk group as your destination, as in the following example:

CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT ‘+dgroup1’;