The Treaty of Versailles is blamed for being the spark of the war. There was a whole bunch of instability in Western Europe and this treaty for Germany at blame for WW1 so Hitler was angry and wanted to take over all of Europe, starting with his country (where he was born) Austria-Hungary
The answer is either A. or C, but I believe that the answer would be A.
Blood typing, HLA typing, and cross-match testing.