In stalin's option, why did the ussr decide to go to war with germany? a. because war was forced upon them by hitler b. because the ussr wanted to acquire german land to expand their territory c. because their troops were ready to fight d. because the united states requested their assistance in the war

The best answer is A) Because war was forced upon them by Hitler

Stalin was no idealist, and had no issue with letting Hitler run amok in Europe, the Mediterranean, and the Middle East. He pursued a neutrality agreement with Japan and, in 1940, was in the process of negotiating a similar treaty with Hitler. Stalin wanted some non-German European territory out of the deal, and Hitler decided that he'd prefer to invade the Soviet Union.
 In this way, Germany forced the USSR to ally with the Allies, although it could very well have sided with the Axis if things had turned out differently. 

Best answer is A