Final answer:
The Russian Revolution of 1917 led to the end of Tsarist rule in Russia and the country's withdrawal from World War I, which answers the question as option b. Russia to leave the war.
Step-by-step explanation:
The Revolution of 1917, specifically known as the Russian Revolution, led to significant political changes within the Russian Empire. The revolution in Russia resulted in the collapse of the Tsarist state, and subsequent political turmoil ensued with a civil war between the Bolsheviks and other factions within Russia. This period of instability culminated in Russia signing a separate peace treaty with Germany called the Treaty of Brest-Litovsk, leading to Russia leaving the war.
As a direct consequence, the correct answer to the question is b. Russia to leave the war. Germany, having been freed up from fighting on the Eastern Front, refocused its efforts on the Western Front. However, it is crucial to note that despite this initial advantage for Germany, it ultimately did not result in them winning the war, as the involvement of the United States and other factors contributed to the eventual victory of the Allied Forces.
The other options, such as France leaving the war, Britain winning the war, or the collapse of the Ottoman Empire, were not direct results of the Russian Revolution. Although the Ottoman Empire did eventually collapse, this was due to a long period of decline and various other contributing factors, not solely the Russian Revolution of 1917.