Refer to the exhibit. The Ethernet interface on Router2 goes down and the administrator notices that the route is still valid in the routing table of Router1. How much longer will it take for Router1 to mark the route invalid by setting the metric to 16?

Refer to the exhibit. The Ethernet interface on Router2 goes down and the administrator notices that the route is still valid in the routing table of Router1. How much longer will it take for Router1 to mark the route invalid by setting the metric to 16?

90 seconds
155 seconds
180 seconds
255 seconds