loyalty and allegiance mean faithfulness owed by duty or by a pledge or promise. loyalty is used of a very personal or powerful kind of faithfulness. I felt great loyalty to my teammates. allegiance is used of a duty to something other than a person, especially to a government or idea. I pledge allegiance to the flag.An example of loyalty is how a dog feels about its human.
It is not even clear what the author would be selling. Also, they're not trying to entertain or persuade; there is no indication of this; so the best answer is "to inform".