Explanation: Receiver sensitivity measures a radio's ability to detect weak signals. For FM receivers, sensitivity is often specified by the "10 dB quieting" method. This indicates the minimum signal level, in microvolts (µV), required to reduce the background noise (static) by 10 decibels relative to no signal. A 10 dB quieting signal provides good, clear voice reception. A sensitivity of 1 microvolt for 10 dB quieting (B) is considered a standard and practical value for a VHF marine receiver. It's sensitive enough to reliably pick up signals from other vessels or shore stations at a useful range without being overly complex or expensive to manufacture. 0.1 microvolt (A) would be exceptionally sensitive, typically found in high-performance amateur radio gear, and might be overly susceptible to noise or strong signal overload in a marine environment. 5 microvolts (C) and 10 microvolts (D) indicate less sensitive receivers, which would significantly limit the practical communication range and performance of a marine radio.