Final answer:
Jane's reaction to the proposal and letter is skeptical but curious. The correct answer is option D).
Step-by-step explanation:
Jane's reaction when Elizabeth tells her about the proposal from Darcy and his letter discrediting Wickham is skeptical but curious.
In the given text, Jane is described as thoughtful and debating the duplicity of men. This suggests that she is not easily swayed and takes a cautious approach in forming her opinions. While she may have some doubts or reservations, she is also intrigued and interested in learning more about the situation.