The immediate cause of the revival of human rights in the post-Second World War period was the growing knowledge of the brutal atrocities committed by the Nazis against the Jews. This option highlights the significant role played by the Holocaust in raising awareness about the violation of human rights.

Option 1, the massive loss of lives in the war, relates to the overall consequences of the war, but it does not directly explain the revival of human rights specifically.

Option 2, the nuclear bombing of Hiroshima and Nagasaki, is a significant event that influenced international relations and the formation of human rights organizations such as the United Nations. However, it is not the immediate cause of the revival of human rights.

Option 4, the emergence of the Soviet Union as a superpower, does not directly relate to the revival of human rights. The Soviet Union`s rise to power had an impact on the global political landscape but is not directly linked to the renewed focus on human rights.

Therefore, the correct answer is option 3: growing knowledge of brutal atrocities of Nazis over the Jews.