The last extermination camp was

Stutthof concentration camp

It was also the last camp liberated by the Allies on 9 May 1945. It is estimated that between 63,000 and 65,000 prisoners of Stutthof concentration camp and its subcamps died as a result of murder, starvation, epidemics, extreme labour conditions, brutal and forced evacuations, and a lack of medical attention.

D. the invasion of Belguim by German troops was only one of the MANY causes of the war