What are the six cities the question asks about
D would be the correct answer
Answer:
This is an article so it is a secondary source.
Explanation:
Secondary: (in academic research) a book, article, or other source that provides information about an object of study but does not constitute direct, first-hand evidence.
Primary: (in academic research) a document, first-hand account, or other source that constitutes direct evidence of an object of study.
