In the 1917 Revolution, the Bolsheviks overthrew the government led by Alexander Kerensky. Alexander Kerensky was a prominent political figure in Russia and served as the head of the Provisional Government after the abdication of Tsar Nicholas II.

Option 1: Alexander Kerensky - This is the correct answer. Alexander Kerensky was the head of the government that was overthrown by the Bolsheviks in the 1917 Revolution.

Option 2: Prince Lvov - Prince Lvov was the first Prime Minister of the Russian Provisional Government, but he resigned just a few months before the Bolshevik Revolution. Therefore, he was not the head of the government that was overthrown by the Bolsheviks.

Option 3: Grand Duke Sergei - Grand Duke Sergei was a member of the Russian royal family, but he did not hold a significant political position during the 1917 Revolution. Therefore, he was not the head of the government that was overthrown by the Bolsheviks.

Option 4: Tsar Nicholas II - Tsar Nicholas II was the last emperor of Russia, and he was overthrown in the February Revolution of 1917. However, he was not the head of the government that was overthrown by the Bolsheviks