Answer:
D. Detailed descriptions of natural phenomena.
Step-by-step explanation:
The best piece of evidence that the author could provide in this case would be detailed descriptions of natural phenomena. This is because the author tells us that both Emily and Charlotte relied on nature to convey their feelings and ideas in their texts. We learn that both authors describe images of natural phenomena in their work. Therefore, if we were able to see an example of this, the claim would be better supported.