Answer: D) “I swear she cast a shadow white as stone.”
Step-by-step explanation: a simile is a figure of speech that consists in making a comparison between elements that aren't obviously related, this comparison is made using the words "like" or "as". In the given excerpt from the poem "I Knew a Woman" by Theodore Roethke we can see an example of simile in the phrase “I swear she cast a shadow white as stone” which also indicates a thoughtful mood.