If a DOWN/UP event occurs on the RTA serial port Serial0/1 during network operation, what can we learn from the above information?

Two routers are connected together through a LAN to form a VRRP backup group. The configuration on each interface is as follows:

[RTA-GigabitEthernet1/0] display this

IP address 192.168.0.252 255.255.255.0

Vrrp vrid 1 virtual-ip 192.168.0.254

Vrrp vrid 1 priority 120 vrrp vrid 1 preempt-mode

Vrrp vrid 1 track interface serial0/1 reduced 30

[RTB-GigabitEthernet1/0] display this

IP address 192.168.0.253 255.255.255.0

Vrrp vrid 1 virtual-ip 192.168.0.254 vrrp vrid 1 preempt-mode

If a DOWN/UP event occurs on the RTA serial port Serial0/1 during network operation, what can we learn from the above information?
A . During the DOWN/UP period of the RTA serial port Serial0/1, the router that responds to the ARP request of the LAN PC will not change.
B . During the RTA serial port Serial0/1 DOWN/UP period, the router that responds to the LAN PC ARP request changes once
C . During the DOWN/UP period of RTA serial port Serial0/1, the router that responds to the ARP request of the LAN PC changes twice
D . During the DOWN/UP period of RTA serial port Serial0/1, the router that responds to the ARP request of the LAN PC changes 3 times