Which type of network can span several building, but is usually less than 30 square miles big?

Networks sit on a scale from smallest to largest coverage area: LAN (one building), then the next size up, MAN (a whole city), and WAN (a country or the globe). Between a single-building LAN and a city-wide MAN sits a network that can stretch across several buildings on one site, such as a university or company campus, while still being confined to a fairly small area.

This is the Campus Area Network (CAN). It is larger than a LAN because it links multiple buildings, but it is still limited in size, typically covering less than about 30 square miles, which is far smaller than the city-wide reach of a MAN or the national and global reach of a WAN.

Exam takeaway: the key distinguishing detail in this question is the phrase several buildings combined with a size limit well under a full city, which points specifically to a Campus Area Network rather than a LAN, MAN, or WAN.