Which event started World War I?
a. the sinking of the Lusitania by German U-boats
b. the assassination of Archduke Franz Ferdinand and his wife, Sophie
c. Germany’s annexation of Alsace and Lorraine after the Franco-Prussian War
d. the Russian enforcement of Pan-Slavism throughout Slavic nations
e. the signing of treaties in 1839 and 1867 to protect Belgium’s neutrality