The correct answer is "He increased the size of his military"
The Treaty of Versailles, after World War I, limited the size of the German military to 100,000 men total at any given time.
Instead of abiding by this number, Hitler constantly increased the size of his military by at least 100,000 each year. Between 1935-1945, roughly 18 million men would serve under the German military. This showed that Hitler blatantly broke the Treaty of Versailles.