Final answer:
A. Charles Ellet owned a high hat and Spanish cape. The least necessary detail from the passage is that Charles Ellet owned a high hat and Spanish cape.
Step-by-step explanation:
The least necessary detail from the passage to explain the topic is: Charles Ellet owned a high hat and Spanish cape. This detail does not contribute to the understanding of the topic of the story, which is about a kite called Union. The details from the other options all provide relevant information about the kite, such as where the best winds blow from and what happened to Homan Walsh later in the story.