Answer:
a. popularized the idea of the United States as a melting pot of ethnicities.
Step-by-step explanation:
These letters were written before the American Revolution War, in many ways, represented the development of an idea about the America that was emerging in the 18th century. It was an ideal society, with no aristocracy, no religious intolerance, and most importantly, a society formed by several cultures and people from around the world, promoting diversity.