Refer to the exhibit.

Which VRRP statement about the roles of the master virtual router and the backup virtual router is
true?

A.
Router A is the master virtual router, and router B is the backup virtual router. When router A
fails, router B becomes the master virtual router. When router A recovers, router B maintains the
role of master virtual router.

B.
Router A is the master virtual router, and Router B is the backup virtual router. When Router A
fails, Router B will become the master virtual router. When Router A recovers, it will regain the
master virtual router role.

C.
Router B is the master virtual router, and router A is the backup virtual router. When router B
fails, router A becomes the master virtual router. When router B recovers, router A maintains the
role of master virtual router.

D.
Router B is the master virtual router, and router A is the backup virtual router. When router B
fails, router A becomes the master virtual router. When router B recovers, it becomes the master
virtual router role.

Explanation:
An important aspect of the VRRP redundancy scheme is VRRP router priority.
Priority determines the role that each VRRP router plays and what happens if the master virtual
router fails.
If a VRRP router owns the IP address of the virtual router and the IP address of the physical
interface, this router functions as a master virtual router.
Priority also determines if a VRRP router functions as a backup virtual router and determines the
order of ascendancy to becoming a master virtual router if the master virtual router fails. You can
configure the priority of each backup virtual router with a value of 1 through 254, using the vrrp
priority command.
For example, if Router A, the master virtual router in a LAN topology, fails, an election process
takes place to determine if backup virtual Routers B or C should take over. If Routers B and C are
configured with the priorities of 101 and 100, respectively, Router B is elected to become master
virtual router because it has the higher priority. If Routers B and C are both configured with the
priority of 100, the backup virtual router with the higher IP address is elected to become the
master virtual router.
By default, a preemptive scheme is enabled whereby a higher-priority backup virtual router that
becomes available takes over for the backup virtual router that was elected to become master
virtual router. You can disable this preemptive scheme using the no vrrp preempt command. If
preemption is disabled, the backup virtual router that is elected to become master virtual router
remains the master until the original master virtual router recovers and becomes master again.
ce: Implementing VRRP on Cisco IOS XR Software
http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.5/addr_serv/configuration/guide/ic35vrrp.html