Hartford, Connecticut, is the location of many insurance and financial services firms such as Uniprise, Travelers, The Hartford, and Aetna. Historically, Hartford was considered the insurance capital of the world and still bears this nickname. According to the lecture The Power of Place, this description makes Hartford a good example of:
A. Agglomeration.
B. Urban gentrification.
C. A central business district.
D. A metropolis.