CompTIA Server+

Answer - D - Rack-mounted servers are used to optimize space needed to place the server.

Key Takeaway: A rack-mounted server is a computer built into a special case, instead of a stand-alone case, like a desktop or tower case. This can be slotted into an industry standard 19-inch equipment rack. For servers to use this rack format, they need to be in cases that will fit the standard dimensions. The cases need to have mounting brackets at the front with holes drilled in the correct places to match up with the holes on the posts.