Explanation: In display system power supplies, particularly switching mode power supplies (SMPS) or those driving backlights, an inverter's primary role is to convert a DC input into a rapidly switched, high-frequency pulsed DC waveform. This pulsed DC effectively acts as a high-frequency AC signal for a small, efficient power transformer. The transformer then steps up this voltage to the levels required for the display, such as high voltage for CCFL backlights or other isolated DC rails, which are then rectified and regulated. Option A is incorrect; inverting DC polarity is a different function, often handled by charge pumps or specific converter topologies. Option B is incorrect as an inverter doesn't specifically provide a dual-polarity 12V supply; that would involve additional rectification and regulation stages. Option C is incorrect because voltage regulation is typically performed by separate circuits or feedback loops, not the inverter itself, which focuses on the DC-to-AC conversion for the transformer.