Question

how did russias withdrawal affect the german war effort?
the withdrawal allowed germany to make great gains on the western front.
the withdrawal inspired germany to start negotiating for peace.
the withdrawal enabled germany to focus its efforts on the ottoman empire.
the withdrawal enabled germany to focus its efforts on the western front.

Explanation:

After Russia withdrew from WWI via the Treaty of Brest-Litovsk in 1918, Germany was able to transfer hundreds of thousands of troops from the Eastern Front to the Western Front, concentrating its military resources there to launch a large-scale offensive. The other options are incorrect: Germany's Western Front gains were temporary and not "great" in a decisive sense; Russia's withdrawal did not prompt Germany to negotiate peace (it fought on); and Germany did not shift focus to the Ottoman Empire, as the Ottomans were already an ally and the main Allied pressure was on the Western Front.

Answer:

D. The withdrawal enabled Germany to focus its efforts on the Western Front.