Final answer:
Hitler violated the Munich Pact by invading and occupying Czechoslovakia, not any of the other countries listed in the question.
Step-by-step explanation:
Following the Munich Conference in 1938, Adolf Hitler and the leaders of Britain and France reached an agreement that permitted Germany to annex the Sudetenland, which was part of Czechoslovakia. Hitler agreed that he would not pursue further territorial expansion. Nevertheless, in early 1939, Hitler violated the Munich Pact when he ordered German troops to invade and occupy the remaining areas of Czechoslovakia, which was not the action that directly initiated World War II.
The correct answer to the question is: d) Czechoslovakia. The invasion of Czechoslovakia by Hitler broke the Munich Pact in which he had previously agreed to cease further aggression in return for the Sudetenland.