General exam question G7A08

WhyA switchmode power supply's high-frequency operation allows the use of smaller components than a linear power supply needs. A switchmode power supply converts power at a much higher frequency than the AC line, which lets its transformer, inductors, and filter capacitors be physically much smaller than the line-frequency components a linear supply needs, answer C. Faster switching doesn't inherently raise the output voltage, switchmode designs generally need more components (the switching, control, and feedback circuitry) rather than fewer, and they aren't inherently more stable than a well-designed linear supply, so A, B, and D are wrong.