Explanation: The radio's measured output of 1 watt in low power mode is typical. However, 8.5 watts in high power mode is significantly lower than the 25-50 watts expected from most VHF mobile or base radios. Here's why C is correct: * **C) The transmitter output is low in the high power mode but it is still functioning within FCC specifications.** The 8.5-watt output confirms the transmitter is indeed producing RF power, albeit at a reduced level for its high power setting. The FCC primarily sets *maximum* power limits for amateur radio bands (e.g., 1500 watts PEP, but usually lower for specific modes/bands like 50W for 2m FM). It does not specify a *minimum* power output for a given mode or power setting, as long as the transmission is clean and within allocated frequencies. A radio transmitting at 8.5 watts is still "functioning" according to FCC rules, even if it's underperforming for the operator's expectations. The inability to contact stations is a direct result of this low output. Here's why the others are incorrect: * **A) The AF Power Amplifier (PA) may be malfunctioning when the transmitter operates in the high power mode.** This option is incorrect because AF (Audio Frequency) power amplifiers deal with audio signals, not the final RF (Radio Frequency) power output measured by the wattmeter. The issue described is with the RF output power. * **B) Negative feedback in the PA stage may be preventing high amplitude oscillations in the high power mode.** While negative feedback is used in amplifier design for stability and linearity, it's not typically described as "preventing high amplitude oscillations" in a way that directly explains low output power. Reduced output power is more likely due to a fault in a gain stage, driver, or final amplifier rather than feedback preventing desired high output. * **D) The transmitter output will increase in the high power mode with modulation between 75 and 100 percent.** For FM (Frequency Modulation) transmissions, which are standard for VHF voice communication, the RF carrier power output remains constant regardless of the modulation level (how loud you speak or the percentage of deviation). Modulation only changes the frequency, not the power. This statement would be relevant for AM (Amplitude Modulation) but not FM.