The first network was called ________.

A “first computer network” means the first operational wide-area, packet-switched network that linked geographically separate computers so they could exchange data — not a single computer with local terminals, and not just any network that came later.

The network that meets this description was ARPANET (Advanced Research Projects Agency Network), commissioned by the U.S. Department of Defense's ARPA and brought online in 1969. It initially connected four nodes — UCLA, Stanford Research Institute, UC Santa Barbara, and the University of Utah — using the Network Control Program (NCP) as its host-to-host protocol; TCP/IP replaced NCP only later, on 1 January 1983 (the “flag day” switch-over).

Checking this against each name offered:

• CNNET — not a documented name in computer-network history; no verifiable network by this name exists.

• NSFNET — a real network, but built by the National Science Foundation in 1985–86 as a later backbone network, roughly 15 years after 1969.

• ASAPNET — not a documented name in computer-network history; no verifiable network by this name exists.

• ARPANET — matches the 1969 first-network criterion above.

Hence, the first network was ARPANET.