Question

A large number of computers in a wide geographical area can be efficiently connected using

Answer 1

the answer is Wan network

Answer 2

There are different networking methods to virtually connect different modern computers.

And according to the circumstances mentioned in the question;

A large number of computers in a wide geographical area can be efficiently connected using WAN network.

WAN network or "Wide Area Network" is a popular method of modern computer networking to connect computers which are separately situated in a wide geographical area.