Answer:
Option B is the correct answer.
Step-by-step explanation:
Christina Rossetti was an English poet who explored different topics such as romantic and children's poems.
In this case, the theme of the poem (the main idea) is that life is a struggle, but there is rest at the end. It can be seen from the beginning, since there's uncertainty in every stanza related to different topics. At the very end of the poem the speaker says that Yea, beds for all who come, meaning that there will be rest. So, option B is the answer.