_____ are written by the subjects themselves.HistoriesAutobiographiesSecondhand biographiesFirsthand biographies

The correct answer is Autobiographies.

Detailed Explanation:

Autobiographies are literary works in which individuals write about their own lives, detailing their experiences, thoughts, and feelings. Unlike biographies, which are written by someone else regarding an individual's life, autobiographies provide a personal perspective, allowing the author to convey their unique insights and reflections directly.

In contrast:

• Histories are typically accounts of past events and are not necessarily personal.
• Secondhand biographies are written by someone who has researched another person's life, rather than being penned by the subject.
• Firsthand biographies is not a commonly used term; the correct terminology for such narratives is "autobiographies".

Thus, the answer to your question is clearly Autobiographies.