CompTIA Server+

Answer - D - The main advantage of having a server rack is that server racks have low friction rails for easy access.

Key Takeaway: A server rack contains multiple mounting slots, called bays, each designed to hold a hardware unit secured in place with screws. Rack equipment chassis slide smoothly in and out on low-friction rails for easy access. A single rack can contain multiple servers stacked one above the other, consolidating network resources and minimizing the required floor space.