Answer:
D. Germany
Step-by-step explanation:
In 1939, Britain and France requested Germany to abandon Poland, a deadline headed by Chamberlain was ignored by the German Nazi regime and thus the beginning of World War 2 had begun.
As the Germans didnt not withdraw from Polish territory, the Western front became the scenario for the following battles, as Polish were in 2 weeks defeated. Germany had used the Blitzkrieg tactics for the first time , rendering a quick and decisive victory with a less powerful neighbour, attacking by surprise.
Soon would France will fear the same tactics and be quickly neutralized in the Western Front.