Explanation:
He is saying "compared to this love we share". The whole poem is centered around the supremacy of their love above all else. In the preceding line, he states that she is all states and he is all princes, and that nothing else is. Compared to their divine and regal love, princes are only imitating their greatness with their meager possessions.
I would choose a. Simply because the author talks about it as if it's all that really ever existed and that nature cannot take over what it is not. However, it goes on about seeing how erosion and rot can affect such things and tries to compare it to things in nature as if it were nature itself.
I believe this is descriptive text.
