The correct answer is A: Observation of propagation and reception. A purpose of a beacon station as identified in the FCC rules is observation of propagation and reception. Beacons transmit continuously to help operators observe band conditions, propagation patterns, and reception quality. This is the primary regulatory purpose of beacons. For amateur radio operators, beacons are valuable tools for assessing band conditions and propagation. Understanding this helps explain why beacons are permitted and how they're used.