On which of the following HF frequencies can automatically controlled amateur propagation beacons be found?

Propagation beacons are used to determine band conditions. Because they run automatically and transmit continuously or on a set schedule, they must be restricted to specific frequency subbands to prevent them from interfering with regular two-way communications. In the 10-meter band, which is the only HF band where Technicians have phone and data privileges, this beacon subband is strictly designated between 28.200 MHz and 28.300 MHz. Other options are incorrect because beacons are not permitted 'anywhere' just by FCC registration, nor are they scattered throughout all Technician subbands. They are carefully coordinated within the specific 28.200 to 28.300 MHz segment on 10 meters.