What was one of the causes of tensions in Europe that led to World War I?

Athe nations in Eastern Europe wanted to unite as a single nation under the Ottoman Empire.

BGermany, Austria-Hungary, and Russia promised to send military support if a war broke out in Europe.

CFrance, Germany, and other nations were competing for overseas territory in Africa and other places.

DBritain cut off Germany’s supply ships, and the German people were slowly starving.