You administer a network that uses two routers， R1 and R2， configured as an HSRP group to  provide redundancy for the gateway. Router R1 is the active router and has been configured as  follows：  
R1#configure terminal  
R1（config）#interface fa0/0  
R1（config-if）#ip address 10.10.0.5 255.255.255.0  
R1（config-if）#standby 1 priority 150  
R1（config-if）#standby preempt delay minimum 50  
R1（config-if）#standby 1 track interface fa0/2 15  
R1（config-if）#standby 1 ip 10.10.0.20  
Which of the following describes the effect the standby preempt delay minimum 50 command will  have on router R1？（）

Routers R1 and R2 are configured for HSRP as shown below：  
Router R1：  
interface ethernet 0  
ip address 20.6.2.1 255.255.255.0  
standby 35 ip 20.6.2.21  
standby 35 priority 100  
interface ethernet 1  
ip address 20.6.1.1.2 255.255.255.0  
standby 34 ip 20.6.1.21   
Router R2：  
interface ethernet 0  
ip address 20.6.2.2 255.255.255.0  
standby 35 ip 20.6.2.21  
interface ethernet 1  
ip address 20.6.1.1.1 255.255.255.0  
standby 34 ip 20.6.1.21 
standby 34 priority 100  
You have configured the routers R1 & R2 with HSRP. While debugging router R2 you notice very  
frequent HSRP group state transitions. 
What is the most likely cause of this？ （）