The correct answer is D: Stub match. A stub match is a matching system that uses a short length of transmission line connected in parallel with the feed line at or near the feed point. The stub provides reactance to cancel the antenna's reactive component. A stub match uses a short section of transmission line (open or shorted at the far end) connected in parallel with the main feed line. The stub's length and termination (open or short) are chosen to provide the right reactance to cancel the antenna's reactance, making the impedance purely resistive and matched. Stub matches are commonly used because they're simple and effective. They can be made from the same transmission line as the feed line, making them convenient. The stub is typically 1/4 wavelength or less.