正解:D
The configuration snippet shown is for HSRP (Hot Standby Router Protocol) on a Cisco router interface. It indicates that preemption is enabled with a delay sync of 100 seconds. This means if R1 fails and then regains operational status, it will wait for 100 seconds before attempting to become the active router again, allowing time for routing protocols to converge. References := Cisco Implementing and Operating Cisco Service Provider Network Core Technologies Course