Which provision of the Treaty of Versailles had the greatest economic impact on Germany? Germany had to spend money to rebuild its military. Germany had to buy back lands claimed by the Allies. Germany had to pay huge reparations for the damages it caused. Germany had to pay large fees to join the League of Nations.
The largest economic impact on Germany following Versailles was the fact that Germany had to pay huge reparations for the damages it (and other opposing states) caused. The costs of these reparations took a huge toll on the democratic Weimar Government in Germany to the point where the nation slipped into crippling depression. The economic downturn tied to the Weimar Regime stoked a great deal of animosity against the democratic government paving the way for radical political movements in Germany like Hitler's Nazi Party. So, the answer is D.