Answer:
C. The systematic killing of Jews by Nazis.
Step-by-step explanation:
This systematic killing took place during World War II. This was caused by the rise of Adolf Hitler. In his famous book, Mein Kempf, Hitler blamed Jews for all of German's economic and political problems. This is why when he became one of the most powerful men in the world, he created a system to kill these Jewish citizens. Over the course of roughly 6 years, Hitler's system would kill 6 million Jewish people from all over Europe.