After world war ll the world discovered that nazi Germany had murdered millions of innocent people as part of the holocaust. Seeing that human being could treat one another so horribly changed the way many people looked at war, government, and minority rights. How could these changes have impacted the study of history

A:changing the way historians interpreted past events

B:making historians more reliant on secondary sources

C: preventing many people from making historical arguments

D:causing pre-holocaust sources to lose validity

The disclosure of the Holocaust to the international community at the end of World War II in 1945 had the effect of having historians change the way they interpreted past events. The parameters used up to that moment had been stated in terms of economic, social and political terms that failed to explain the motivations that drove Germany, considered as one of the most civilized nations in the world, to mass murder millions of human beings on a racist basis. The importance of psychological profiling of the political leaders who staged the Holocaust became absolutely necessary to interpret this horrendous human experience.