What control method delivers status messages, report errors, and is used to test connectivity?
Explanation
Answer: C - Internet Control Message Protocol (ICMP) delivers status messages, report errors, and is used to test connectivity. ICMP also indicates when problems occur with a specific route on the network and tells surrounding routers about better routes to take based on the health and congestion of the various pathways. Routers use ICMP to send messages in response to data grams that could not be delivered. ICMP is used by other connectionless protocols, not just IP, because connectionless protocols do not have any way of detecting and reacting to transmission errors, as do connection-orientated protocols. Under these conditions, the connectionless protocol may use ICMP to send error messages back to the sending system to indicate networking problems.
