Why did Mr. de Leeuw’s plan to go to Switzerland fail? with textual evidence questions is about the upstairs room

Switzerland maintained a state of armed neutrality during the first world war. However, with two of the Central Powers (Germany and Austria-Hungary) and two of the Entente Powers (France and Italy) all sharing borders and populations with Switzerland, neutrality proved difficult. Under the Schlieffen Plan, the German General Staff had been open to the possibility of trying to outflank the French fortifications by marching through Switzerland in violation of its neutrality, although the plan's eventual executor Helmuth von Moltke the Younger selected Belgium instead due to Switzerland's mountainous topography and the disorganized state of the Belgian Armed Forces.[1] From December 1914 until the spring of 1918, Swiss troops were deployed in the Jura along the French border over concern that the trench war might spill into Switzerland. Of lesser concern was the Italian border, but troops were also stationed in the Unterengadin region of Graubünden

Explanation:

it is the : d because is true

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