Which primary source document could a historian understand why the us civil war started? a. a map of the 1860 presidential election results b. a map showing where the first battles occurred c. a charleston mercury editorial published in 1860 d. an essay that lists several possible causes

The correct answer is C. A Charleston Mercury editorial published in 1860

Explanation:

To begin with, a primary source is a source created during the event being studied by someone who witnessed or experienced it. This implies if a historian is trying to understand the causes of the Civil War through a primary source he needs to focus on sources that were created before 1861 when this war started.

Moreover, as the focus is the causes of the Civil War the best type of source is one that analyzes the situation of the American society around 1861 and depicts the factors that contribute to the war. Considering this, the best document is "A Charleston Mercury editorial published in 1860" because this is a primary source and through this, the historian can understand the social situation and factors that lead to the war, which is the focus of the historian.