What happens when the whole CONTROLLER1 Failure group is damaged?

A database instance is using an Automatic Storage Management (ASM) instance, which has a disk group, DGROUP1, created as follows:

SQL> CREATE DISKGROUP dgroup1 NORMAL REDUNDANCY
FAILGROUP controller1 DISK ‘/devices/diska1’, ‘/devices/diska2’
FAILGROUP controller2 DISK ‘/devices/diskb1’, ‘/devices/diskb2’ ;

What happens when the whole CONTROLLER1 Failure group is damaged?

A.
The transactions that use the disk group will halt.

B.
The mirroring of allocation units occurs within the CONTROLLER2 failure group.

C.
The data in the CONTROLLER1 failure group is shifted to the CONTROLLER2 failure group and implicit rebalancing is triggered.

D.
The ASM does not mirror any data and newly allocated primary allocation units (AU) are stored in the CONTROLLER2 failure group.

Explanation:
Oracle Press 1Z0-053 Exam Guide, Chapter 1: Database Architecture and ASM

Whenever you change the configuration of a disk group-whether you are adding or removing a failure group or a disk within a failure group-dynamic rebalancing occurs automatically to proportionally reallocate data from other members of the disk group to the new member of the disk group. This rebalance occurs while the database is online and available to users. Any impact to ongoing database I/O can be controlled by adjusting the value of the initialization parameter ASM_POWER_LIMIT to a lower value.