Final answer:
A map can be either a primary or secondary source depending on its creation time and context. A contemporaneously made map is a primary source, while one made later as a historical representation is a secondary source. Additionally, the purpose for which the map is used can also determine its classification.
Step-by-step explanation:
A map can be considered a primary source or a secondary source depending on when and how it was created. If a map is drawn at the time of the events it is depicting, it is a primary source. For example, a map created by a military commander during a historical battle would be a primary source because it was created at the time of the events it represents. On the other hand, if a map is created after the fact, such as a map drawn in the 1960s to identify battle sites of World War II, then it is a secondary source because it was created after the events it illustrates.
Furthermore, the use of the map also influences whether it is a primary or secondary source. For instance, the mentioned 1960s map of World War II battle sites, while a secondary source about the war, could be a primary source in studying the historical interpretation or educational approach taken during the 1960s.
As for the example provided in the review question, an example of a primary source would be option (a) a diary entry by a person who lived in the period under discussion.