Clarifier/elaborator because this person could help other people understand different viewpoints by clarifying them and making it easier.
The early attempt at sleep teaching failed in the Brave New World story because they did not consider the strength of a child's mind. The early attempt was made with an objective to increase a child's intellectual ability. The experiment resulted in the child's ability to memorize the sleep teaching material but he/she has no idea of it.
I think the answer is A) true.