When the ICMP message of time exceeded the error occurred value of the value of time to live field is 0. When the datagram visits a router, the value of time to live field remains constant, that is, 0.Important Point:ICMP works on the network layer. ICMP is an error-reporting protocol network devices like routers use to generate error messages to the source IP address when network problems prevent delivery of IP packets. ICMP creates and sends messages to the source IP address indicating that a gateway to the Internet that a router, service, or host cannot be reached for packet delivery. Any IP network device has the capability to send, receive or process ICMP messagesThe ICMP Time Exceeded message notifies a host when a packet it sent has been discarded because it was "out of time." Packets are not actually timed, but to prevent packets from being forwarded forever when there is a routing loop, each IP packet header includes a Time to Live (TTL) fieldThe TTL field will be decremented by 1 at every router and will be zero by the time it reaches the source. Confusion Point:Different website has given answer 4 but it is incorrect. Official key say option 1 is correct