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

A documentary film about a historical event is an example of a secondary source because it analyzes, interprets, or summarizes information from primary sources rather than presenting original data or firsthand accounts. Secondary sources provide context, commentary, or a more comprehensive overview of a subject based on existing materials. In this case, the documentary would likely compile various primary sources—such as documents, interviews, and firsthand accounts related to the historical event—to create a cohesive narrative or analysis.

In contrast, a personal interview with an eyewitness represents firsthand testimony and is therefore considered a primary source. An original research study is also a primary source, focused on presenting new findings or data generated by the researchers themselves. Similarly, a statistical report based on survey data would be primary if it presents data directly collected from individuals via the survey, although it can also qualify as secondary if it summarizes existing survey findings from prior studies. However, the key distinction for identifying a secondary source lies in its role of presenting derived insights or commentary rather than original data or direct evidence.