单项选择题
A. On DS1， disable preempt
B. On DS1， decrease the priority value to a value less than 190 and greater than 150
C. On DS2， increase the priority value to a value greater 241 and less than 249
D. On DS2， increase the decrement value in the track command to a value greater than 10 and less than 50.
单项选择题 During routine maintenance， G1/0/1 on DS1 was shutdown. All other interface were up. DS2 became the active HSRP device for Vlan101 as desired. However， after G1/0/1 on DS1 was reactivated. DS1 did not become the active HSRP device as desired. What need to be done to make the group for Vlan101 function properly ？ （）
单项选择题 Refer to the exhibit. Which Virtual Router Redundancy Protocol （VRRP） statement is true about the roles of the master virtual router and the backup virtual router？（）
单项选择题 Refer to the exhibit. Switch S2 contains the default configuration. Switches S1 and S3 both have had the command spanning-tree mode rapid-pvst issued on them. What will be the result？（）