To engage the reader, the author of a specific text should ask a thought-provoking question.
A thought-provoking question helps the reader to become more reflective or, in other words, to think things through. Furthermore, by introducing a thought-provoking question, the writer can contribute to make the reader more interested in the text. On the other hand, using a quotation or presenting facts will not stimulate the reader's thoughts. Moreover, giving an anecdote may increase the reader's interest in the text but will not provoke him/her to think either.