In 1941 Hitler was confident about invading Russia because he had recently captured

Spain.

France.

Great Britain.

Switzerland.

France

Explanation:

Hitler played very sneaky during the World War II. He attacked France quickly and without any warning through Belgium, as that part of France was not well defended. The German army managed to win battle by battle and soon invaded all of France. This led Hitler to believe that he can now give orders to attack and invade Russia. Hitler and Stalin actually had an agreement with which they obliged themselves to not attack one another during the war, and that they do not interfere with each others zones of influence. Hitler saw this as an advantage, as Stalin considered him as a friend and thought that Hitler would not stab him in the back. He was wrong though, and Hitler ordered his army to attack Russia. Stalin was devastated by this move, and Russia was caught unprepared. But as many times in the past, Russia saved itself because of its harsh winters. The Germans were badly damaged by the long, very cold, snowy winter, and the Russians used that in their advantage and managed to defeat the Germans, marking the beginning of their end.

B) France