Final answer:
A primary source of data is firsthand material or information like personal narratives, eyewitness accounts, and original documents. The correct example of a primary source is 'a diary entry by a person who lived in the period under discussion'.
Step-by-step explanation:
A primary source of data is original material or information that has not been interpreted by another person. Examples of primary sources include personal narratives, diaries, eyewitness accounts, interviews, original documents like treaties or official certificates, newspaper coverage of events at the time they occurred, scientific observations, and experimental data. In the context of research, primary data is collected or conducted firsthand by the researcher.
When answering the question of which is an example of a primary source, option a, 'a diary entry by a person who lived in the period under discussion', is a correct choice. This is because a diary provides a firsthand account of the person's experiences and thoughts during a specific time period. On the contrary, secondary sources like biographies or textbooks interpret and analyze primary data instead of providing it directly.
Primary sources are crucial for creating your own analysis with the appropriate rhetorical approach. They enable the research to provide a fresh perspective on a subject, whether you're studying a historical event or analyzing data from a scientific experiment.