Final answer:
The correct answer is A. a section in a history textbook that covers the Freedom Riders.
Step-by-step explanation:
A primary source is an original document or firsthand account that provides direct evidence or information about a specific topic or event. Options B, C, and D all provide primary sources that Guillermo could use for his research on the Freedom Riders:
- Option B, a set of photographs of the Freedom Riders depicting their protests, is a primary source because it provides visual evidence of the events that took place.
- Option C, a letter written by one of the Freedom Riders about her experience, is a primary source because it offers a firsthand account of the events.
- Option D, a news report from the era that features interviews with some Freedom Riders, is a primary source because it provides direct information from individuals who were involved in the events.
Option A, a section in a history textbook that covers the Freedom Riders, is not a primary source because it is a secondary source. Secondary sources are interpretations or analyses of primary sources created by someone who was not directly involved in the events.