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

Answer: D. On ten meters, between 28.200 MHz and 28.300 MHz

Automatically controlled beacons on HF are limited to ten meters, between 28.200 MHz and 28.300 MHz, under FCC rule 97.203. They are not allowed anywhere you like, and there is no FCC registration that changes this.

Tip: Beacons live at 28.2 to 28.3 MHz on 10 meters.

FCC rule reference: Part 97.203(d)