Examples of primary sources do not include

Examples include interview transcripts, statistical data, and works of art. A primary source gives you direct access to the subject of your research. Secondary sources provide second-hand information and commentary from other researchers. Examples include journal articles, reviews, and academic books

Explanation:

Materials that are NOT primary sources include: Books written after a historical event by someone who was not involved in the event. Books are considered Secondary Sources. ... Statistics compiled about a historical event (for example, a tally of the number of dead in a battle)

the answer is b: an economic crisis throughout the country.