Which of the following is an example of a primary source?

A diary entry from an eyewitness is a primary source because it provides direct, firsthand accounts of the experiences and observations of an individual during a specific time period. Primary sources are original documents or evidence created at the time historical events occurred or by individuals directly involved in those events. The content of a diary reflects the personal thoughts, feelings, and narratives of the writer, making it an invaluable resource for historians studying that particular moment in history.

In contrast, the other options involve interpretations or analyses of events rather than direct accounts. A textbook analysis synthesizes information from multiple secondary sources and may not capture the nuances of individual experiences. A magazine article discussing an era typically draws from various primary and secondary sources to present an overview rather than firsthand accounts. Similarly, a documentary film based on interviews, while informative, often edits and interprets those reflections, placing it in the secondary source category rather than providing an unmediated account of an event.