A technician is asked to install three servers: a 1U, a 4U, and a 6U. Which of the following is the MOST correct order to install these servers starting from the top of the rack?

Installing the 1U at the top, 4U in the middle, and 6U at the bottom places the least mass at the highest point, lowering the rack's center of gravity and reducing the risk of tipping. This order follows standard data center best practices for weight distribution and physical stability in open or enclosed racks.

Placing the 4U above the 1U violates the ascending-weight-from-top principle, putting a heavier unit above a lighter one and raising the center of gravity.

Installing 4U then 6U at the top leaves the heaviest equipment in the upper half of the rack, which destabilizes the rack and contradicts best-practice weight distribution guidelines.

Starting with the 6U at the top places the heaviest server at the highest point, which raises the center of gravity and creates the greatest risk of rack instability or tipping.