Well, this is true, but it is really over-simplifying the situation.
The war did not start because Hitler militarized Germany: the rest of Europe still hoped to avoid the war. But it was a step towards the war.
The same with the second option: The take over of Austria and Czekoslovakia were a step towards the war, but not a final one
the final one was Hitler's invasion of Poland, which is a big county.
