The correct answer is A: It has low efficiency. A disadvantage of the short, flexible antenna supplied with most handheld radio transceivers (compared to a full-sized quarter-wave antenna) is that it has low efficiency. Short antennas are much smaller than a quarter wavelength, making them inefficient radiators. Much of the power is lost as heat or reflected back to the transmitter rather than being radiated. For amateur radio operators, understanding this limitation helps explain why handheld radios have limited range and why external antennas improve performance. The trade-off is convenience versus performance.