Question

Which is the best title for the map?

Answer 1

I believe the correct answer is B. German territorial losses after World War I.
As you can see in the map, there are several areas that Germany lost, such as Poland, which became a new country, and an area that now belonged to France. The purple part represents what was left of Germany after WWI, which was still a large portion of Europe, but smaller than it was before the War. 

Answer 2

The correct title for such a map would be:

B. German Territorial Losses after World War I

According to the terms of the Treaty of Versailles, which brought World War I to a close, Germany had to give up large portions of its territory, as shown in the map.  Germany also was forced to give up colonial territories.   The League of Nations (formed after World War I) created a system for governing former German and Ottoman territories, called "the mandate system."  There were mandate territories for former German territories in Africa and Asia, as well for former Ottoman territories in the Middle East.  

So Germany lost territory both in Europe and abroad as a result of World War I.