Which network served as the foundation for the Internet developed by the Department of Defense?

The correct answer is ARPAnet, which is significant as it was the pioneering network that laid the groundwork for the Internet as we know it today. Developed by the Department of Defense in the late 1960s, ARPAnet was designed as a means of secure communication that could withstand potential disruptions, such as those caused by a nuclear attack.

This early network used packet switching technology, which allows for data to be broken into packets and routed separately to their destination, making it far more efficient and robust than traditional circuit-switching methods used at the time. ARPAnet connected various universities and research institutions, allowing for the sharing of resources and information, which fueled advancement in networking technology.

As ARPAnet evolved, it laid the framework for protocols and architectures that are foundational to the Internet, such as TCP/IP. Its establishment set the stage for today's global connectivity, demonstrating the enormous potential of networked communication.

In contrast, the other options mentioned, such as SWIFT, USENET, and CompuServe, while significant in their own right, do not serve as the foundational stones upon which the Internet was built. SWIFT is a network primarily used for financial transactions, USENET is a distributed discussion system