After October, power in Russia became concentrated in the hands of which party?

Correct answer: Russian Communist Party

The correct answer is the Russian Communist Party, which was the Bolshevik Party after it adopted the communist name. Following the October Revolution, the Bolsheviks formed the government and gradually removed or restricted rival political forces. After the Civil War, the Communist Party became the central organisation controlling the state, administration, economy and political decision-making. The British Labour Party belonged to Britain, the Jacobin Club belonged to revolutionary France in the eighteenth century, and the Indian National Congress belonged to India’s anti-colonial movement. None of these could represent the ruling party in post-revolutionary Russia. Therefore, option A is correct.