Trench warfare began after Germany failed in its initial plan to

Germany’s initial plan, the Schlieffen Plan, aimed to defeat France quickly by invading through Belgium before turning to fight Russia. When the advance was stopped at the First Battle of the Marne, the war on the Western Front stalled, and both sides dug trenches. Choice A, “seize France and bring a quick end to the war,” describes the plan Germany failed to carry out.

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