Analyze the map below and answer the question that follows. A political map of Europe. Countries are highlighted and labeled 1 to 6. 1 is on a peninsula next to Portugal. 2 is an island northwest of France. 3 is between Spain and Germany. 4 is southeast of France and shaped like a boot. 5 is between France and Poland. 6 is the largest country next to Finland, Lithuania, Belarus, and Ukraine.

Image courtesy of NASA

Which country labeled on the map above has a population of 81 million people, the second-highest population in Europe?
A.2
B.3
C.5
D.6