Refer to the exhibit.


R1(config)#ip sla 1 R1(config-ip-sla)#icmp-echo 172.20.20.2 source-interface FastEthernet 1/0 R1(config-ip-sla-echo)#timeout 5000 R1(config-ip-sla-echo)#frequency 10 R1(config-ip-sla-echo)#threshold 500 R1(config)#ip sla schedule 1 start-time now life forever R1(config)#track10 ip sla 1 reachability R1(config)#ip route 0.0.0.0 0.0.0.0 172.20.20.2
After implementing the configuration, 172.20.20.2 stops replying to ICMP echos, but the default route fails to be removed. What is the reason for this behavior?

A.	The threshold value is wrong.
B.	The source-interface is configured incorrectly.
C.	The destination must be 172.30.30.2 for icmp-echo.
D.	The default route is missing the track feature.