In co$-$location, a firm:

A$.$ utilizes an external, distributed computing grid.

B$.$ off$-$loads peak demand for computing power to remote, large$-$scale data centers.

C$.$ purchases and owns its web server but locates the server in the physical facility of a hosting service.

D$.$ uses only open source software to operate its computer systems.

E$.$ contracts with an external vendor to run its computer center and networks.