Answer:
The right answer is letter B.
Explanation:
The 1rst willow (who's the main character) is comparing love to the young willow. He's talking from his experience and we can assume he's wise because of his age. He's also reminded of himself by the young willow; who is also shimmering; suffering alone (at the bare woods' edge).
Taking all this into consideration, we can say that the poem supports the theme: "love must be nurtured in order to grow".