Answer:
The correct answer is C. William lives on the Northern European Plain.
Explanation:
Basically, William would not be able to live in the eastern coast of the Caspian Sea, because it is not a plain area, and it is not also in Europe. Regarding the Caucasus Mountains, it is obvious that they are not a plain region. Finally, the Western Siberian Plains are not located in Europe, but in Asia.
The North European Plain is a plain in Europe located on the territory of Poland, Germany, Denmark, as well as Belgium and the Netherlands. It is limited in the north by the coasts of the North and Baltic Seas, and in the south by the mountains and elevations of Hercynian Europe.
The North European Plain is densely populated. On its territory are the cities of Poznan, Berlin, Hamburg, Bremen, Hanover, Amsterdam, Rotterdam.
