What is the frequency of a marker beacon?

The correct answer is 75 MHz because marker beacons, which are used in aviation to signal the position of important locations such as runway thresholds or the location of navigational aid equipment, transmit their signals at this specific frequency. This frequency is standardized in aviation to ensure compatibility and reliability in various aircraft navigation systems. The 75 MHz frequency allows for a clear and distinct reception of signals, which is essential for accurate and safe navigation.

In contrast, the other frequencies mentioned are not designated for marker beacons. Alternative frequencies serve different purposes in the aviation radio spectrum, leading to some confusion but highlighting the importance of knowing the specific applications for each frequency range.