The correct answer is B. I would expect to find the highest population density per square mile in Central Spain, since the capital city of Spain, Madrid, is located in that area.
Explanation:
Within the municipal area of Madrid, the most populated in Spain, there are 3,223,334 registered persons. The associated metropolitan area has a population of 6,507,184 inhabitants, making it the third or fourth of the European Union, according to the source, after those of Paris and London, and in some sources also behind the Ruhr Region, as well as the third most populated city of the European Union, behind Berlin and London.
