The Russian Revolution

During World War I, Russia was part of the Triple Entente alongside France and Great Britain, which formed the core of the Allied Powers (or Allies). They fought against the Central Powers, which included Germany, Austria-Hungary, and the Ottoman Empire.

Following Vladimir Lenin's death in 1924, a power struggle ensued within the Communist Party. Joseph Stalin eventually consolidated power and became the leader of the Soviet Union.

During the Russian Revolution of 1917, Vladimir Lenin and the Bolsheviks gained widespread support by using the simple and powerful slogan 'Peace, Land, and Bread.' This addressed the main grievances of the Russian people: ending participation in World War I (Peace), redistributing land to the peasants (Land), and ending the severe food shortages (Bread).

Prior to World War I, Russia possessed the largest standing army in the world, often referred to as the 'Russian Steamroller' due to its sheer size of millions of soldiers. However, despite its massive numbers, the army suffered from poor equipment, outdated technology, and inadequate leadership.

The Russian Revolution began in 1917 with the February Revolution, which led to the abdication of Tsar Nicholas II, followed by the October Revolution later that year which brought the Bolsheviks to power.

Czar Nicholas II ruled the Russian Empire from 1894 until his abdication in 1917, which spanned most of World War I. The other options are incorrect historical figures or did not rule during this period.