A huge variety of networking hardware and software appeared. One challenge was to enable these different networks to communicate with each other. ARPA accomplished this by developing the , which created a true "network of networks," the current architecture of the Internet.

Internet Protocol (IP) is the correct answer of this question.

Explanation:

This was done by ARPA creating the internet protocol that created a true "network of networks," the current Internet architecture.A huge array of hardware and software networking has emerged. One challenge was to connect with each other through these different networks.

The Internet Protocol (IP) is an interface or set of rules to route and manipulate packets of data so that they can navigate through cables and reach the right goal.

For Example:- tcp, udp, http ,https ,ftp, dns, telnet, bgp etc.

it can either be 2. or 4. : ) tell me if i'm wrong or right

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