Final answer:
The best supporting detail for the Scottsboro Boys case is the false claim made by the two white women, which led to the unfair trials and convictions of the nine black teenagers. Option A is correct answer.
Step-by-step explanation:
The question asks which detail from the text best supports the answer to Part A, which requires identifying evidence that demonstrates an event or situation relating to the Scottsboro Boys case.
The correct answer is A) "They falsely claimed the nine black teenagers had raped them." (Paragraph 3) because it directly addresses the crux of the event that incited the injustices that followed. The allegations were the start of the trials and the subsequent convictions based on racial prejudice rather than factual evidence.
The other options, while related to the case, do not provide the foundational detail that initiated the legal battles of the Scottsboro Boys.