Soviets invade France (CYOAH)

Previous-France answers the call! (CYOAH)

The Soviets know that they need to defeat an enemy sending forces from Scandinavia to France and the Soviets suppress the rebels moving to Hamburg and defeating the germans. The Soviets moved into Alslace-Lorraine defeating the French and pushing further and further into France. meanwhile the President of Germany has fled to Britain with a Scientist named Albert Einstein but another scientist named Pavel Oleynikov has begun working for the USSR, who builds the atom bomb first? and where is it dropped?
 * Britain builds the first Atom Bomb and drops it on Moscow
 * Soviets build it first dropping it on Paris
 * Soviets build it and drop it on London
 * Soviets build it first dropping it on Washington D.C.