The correct option is D USSR
The Second World War broke out a mere two decades after the end of the First World War. It was fought between the Axis powers(mainly Nazi Germany, Japan and Italy) and the Allies (Britain, France, the Soviet Union and the US). It was a war waged for six years on many fronts, in many places, over land, on sea, in the air. Once again death and destruction was enormous. At least 60 million people, or about 3 per cent of the world’s 1939 population, are believed to have been killed, directly or indirectly, as a result of the war. Millions more were injured.