Answer is C)
Traceroute is a little program that can run in any Internet host. When the user specifies a destination hostname, the program sends multiple packets towards that destination. As these packets work their way towards the destinations, they pass through a series of routers. When a router receives one of these packets, it sends a little message back to the source. This message contains the name and address of the router. More specifically, suppose there are N-1 routers between the source and the destination. Then the source will send N packets into the network, with each packet addressed to the ultimate destination. These packets are also marked 1 through N, with the first of the N packets marked 1 and the last of the N packets marked N. When the nth router receives the nth packet marked n, the router destroys the packet and sends a message to the source. And when the destination host receives the Nth packet, the destination destroys it as well but again returns a message back to the source. The source records the time that elapses from when it sends a packet until when it receives the corresponding return message; it also records the name and address of the router (or the destination host) that returns the message. In this manner, the source can reconstruct the route taken by packets flowing from source to destination, and the source can determine the round-trip delays to all the intervening routers. Traceroute actually repeats the experiment just described three times, so the source actually sends 3*N packets to the destination.
The above is taken from Kurose and Ross.
The [RFC 1393] describes traceroute in detail.
ICMP is specified in [RFC 792]. The most typical use of ICMP is for error reporting.ICMP messages have a type and a code field, and also contain the first 8 bytes of the IP packet that caused the IP message to be generated in the first place (so that the sender can determine which packet is sent that caused the error). Selected ICMP messages are shown below:
ICMP type Code Description
0 0 echo reply (to ping)
3 0 destination network unreachable
3 1 destination host unreachable
3 2 destination protocol unreachable
3 3 destination port unreachable
3 6 destination network unknown
3 7 destination host unknown
4 0 source quench (congestion control)
8 0 echo request
9 0 router advertisement
10 0 router discovery
11 0 TTL expired
Traceroute uses ICMP messages. To determine the names and addresses of the routers between source and destination, Traceroute in the source sends a series of ordinary IP datagrams to the destination. The first of these datagrams have a TTL of 1, the second of 2, the third of 3, etc. The source also starts timers for each of the datagrams. When the nth datagram arrives at the nth router, the nth router observers that the TTL of the datagram has just expired. According to the rules of the IP protocol, the router discards the datagram (because there may be a routing loop) and sends an ICMP warning message to the source (type 11 code 0). This warning message includes the name of the router and its IP address. When the ICMP message corresponding to the nth datagram arrives at the source, the source obtains the round-trip time from the timer and the name and IP address from the ICMP message.