<span>B.They suggest that the beauty of the natural world is fleeting and cannot compare to the lasting beauty of two mature people who love one another.</span>
Option D. The details in the words written near the end of "The River Merchant's Wife: A Letter" develop the idea that time and maturity can allow love to develop between two people, as they suggest that<u> the speaker is no longer the innocent girl or the bashful bride she once was, and she wants to be paired again with her beloved husband.</u>
Explanation:
In the last words of "The River Merchant's Wife: A Letter" the speaker describes how she is hurt by seeing the "paired butterflies", which are "already yellow with August". These words are not only making a reference about how the speaker is no longer that innocent girl of the beginning of the poem, that did not want to speak or did not know what to feel. They are also conveying that she is tired of being separated from her husband, and wants to see him again and be just like the paired butterflies. These words support the main theme of the poem written by Ezra Pound, that is the idea that time and maturity can allow love to develop between two people.