For the first one you should pick B Russia invaded was in the early 40s. The Potsdam conference was held in Germany (Potsdam) after the war. Normandy was in between.
For the second question AC and D are simple nonsense. The opposite is true in at least 2 of them.
For the third one anyone of the Democracies would like C to be true. Pick C although it is questionable.
