Explanation The correct answer is D. Power supply wattage rating. The power supply wattage rating is the most important factor to consider before building a gaming computer, as it determines how much power the system can draw from the wall and how much power the components can consume. A power supply with a low wattage rating may not be able to support the high-end graphics card, processor, and other devices, resulting in poor performance, instability, or damage12. To find the optimal power supply wattage rating for a gaming computer, the technician should calculate the total power consumption of all the components and add some headroom for future upgrades or overclocking. The technician can use online calculators such as Cooler Master Power Calculator or Seasonic Wattage Calculator to estimate the power requirements of the system3.