What is one reason to use an impedance matching transformer at a transmitter output?

Maximum power transfer in any radio system occurs when the output impedance of the transmitter perfectly matches the impedance of the feed line and antenna system. If there is an impedance mismatch, power is reflected back toward the transmitter, which reduces efficiency and can potentially damage the final amplifier stages. An impedance matching transformer bridges this gap by transforming the impedance of the feed line to match what the transmitter is designed to "see" (which is typically 50 ohms). This ensures the transmitter can deliver its full power safely. The options suggesting the transformer minimizes power or reduces ripple are distractors. The goal of impedance matching is always to optimize and maximize efficient power transfer, and ripple is a power supply filtering issue rather than an RF output concern.