Who were the bolsheviks and why were they important

Bolsheviks were the majority group of the workers of Russia, who under the leadership of Lenin, believed in the revolutionary methods for bringing about changes in the society and the state. In their opinion, the parliamentary methods would not be able to bring about any changes in a country like Russia where no democratic rights existed and where there was no Parliament. Ultimately, it was these Bolsheviks who were able to bring about a successful revolution in Russia in 1917 and they changed the whole structure of the state and the society.    

i would say your answer would be the second option.

hope this !