Which of the following is an example of primary research?

Primary research refers to the direct collection of data or original information firsthand, rather than relying on the analysis or interpretation of others’ work. Autobiographies are a clear example of primary research because they are firsthand accounts written by individuals reflecting on their own life experiences. This personal narrative provides original insights and data about the person's life, thoughts, and feelings, making it an authentic source of primary information.

In contrast, textbook summaries, analytical articles, and literature reviews process and summarize existing information rather than presenting new data. Textbook summaries typically condense and explain information from multiple sources without adding original content. Analytical articles analyze or interpret data collected by others rather than generating new data themselves. Literature reviews compile and assess previously published research to present an overview of a field or topic without introducing new research, making them secondary sources. Thus, autobiographies stand out as the correct choice for primary research due to their firsthand nature.