Explanation: A malfunction in a critical safety system like a 2182 kHz radiotelephone must be reported and logged. **B) No indication of power output when speaking into the microphone.** This is a direct indication of a malfunction in the transmitter's ability to generate or radiate RF power. The radiotelephone's primary function is to transmit, especially on a distress frequency. A failure to transmit is a critical fault. **A) Much higher noise level observed during daytime operation.** This is often due to natural atmospheric noise (QRN), which can be significant on MF/HF frequencies like 2182 kHz, particularly during the day or certain solar conditions. It's usually an environmental factor, not a malfunction of the radio equipment itself. **C) When testing a radiotelephone alarm on 2182 kHz into an artificial antenna, the Distress frequency watch receiver becomes unmuted, an improper testing procedure.** This indicates an issue with the testing procedure or setup (e.g., faulty dummy load, inadequate shielding, or too sensitive a watch receiver), not necessarily a malfunction of the 2182 kHz radiotelephone system itself. The radio might be functioning correctly, but the test isn't isolated. **D) Failure to contact a shore station 600 nautical miles distant during daytime operation.** Communication on 2182 kHz (a Medium Frequency) for 600 nautical miles during the day is often challenging or impossible due to propagation limitations. Daytime ground wave range is limited, and skywave propagation can be heavily absorbed. This is typically a propagation issue, not a radio malfunction.