Answer: C) Rhetorical question.
Explanation: When writing, an author can use several rhetorical devices in order to persuade, inform or impact the audience in the desired way. One of the most used rhetorical devices, is a rhetorical question. A rhetorical question is a question asked in order to create a dramatic effect or to make a point rather than to get an answer. In the given excerpt, the author ask about the restrictions of enlightenment in a rhetorical way.