Which pair of ancient civilizations were ruled by dynastys a: china and egypt b: china and the indus river valley c: the indus river valley and mesopotamia or d: egypt and mesopotamia

After world war ii, the world discovered that nazi germany had murdered millions of innocent people as part of the holocaust. seeing that human beings 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?