Which of the following factors is the MOST likely cause of a power supply fan failure?

While extreme temperature variations can stress electronic components, fan failure is more directly caused by physical obstructions or wear from dust rather than temperature fluctuations alone.

Extreme humidity variances can contribute to issues like corrosion or short circuits within electronic components, but they are less directly linked to the mechanical failure of a fan compared to dust accumulation.

Power stability fluctuations primarily affect the electronic components and overall lifespan of the power supply unit, but they are not the main cause of a mechanical fan failure.

Excessive dust accumulation severely impacts fan performance by coating the blades and motor assembly, which increases resistance and reduces airflow. This forces the fan to work harder, generates more heat, and ultimately causes premature wear and failure of the fan's motor or bearings, making it the most likely cause of a power supply fan failure.