Final answer:
The Bolsheviks overthrew the Democratic-Russian government in 1917 and solidified their power in 1918.
Step-by-step explanation:
In what year did the Bolsheviks, a group of communists, overthrow the Democratic-Russian government established? The correct answer is b) 1917, 1918. The Bolsheviks, led by Vladimir Lenin, seized power during the October Revolution of 1917, toppling the provisional government that had been established after the abdication of Czar Nicholas II earlier that year. The Bolsheviks then solidified their control and proceeded to negotiate a peace with Germany in March 1918, marking the end of Russia's participation in World War I.