What increases the low-power output from a handheld transceiver?

Choosing an RF power amplifier as a means to increase the low-power output from a handheld transceiver is the correct choice because RF power amplifiers are specifically designed to take low-level radio frequency signals and amplify them to a higher power level suitable for transmission over distances. This process typically involves increasing the voltage and current of the input signal, allowing it to drive a transmitting antenna more effectively.

In contrast, a voltage divider reduces voltage and is used more for adjusting levels of signal, not amplifying them. An impedance network typically matches the impedance of the transmission line to the load or source, ensuring efficient power transfer but does not amplify power. Finally, a voltage regulator is used to maintain a constant voltage level and does not function to amplify signals. Therefore, the RF power amplifier is uniquely suited for increasing output power in a transceiver, making it the appropriate choice for this scenario.