Answer:
D. They allude to the speaker’s concern that death would deprive his fertile imagination, a field of “full-ripen'd grain,” to be harvested in books.
Step-by-step explanation:
"When I Have Fears that I May Cease to Be" is a sonnet written by John Keats, an English Romantic poet. The sonnet talks about life and how transient it is. It centers on his fear of people's mortality and how life can be very limited, as it limits his ability to write.
He is concerned on how death would prevent him from pouring out his thoughts, ideas and feelings into his books by writing.
So, this explains the answer.