The Russian Revelation, which actually began in February 1917. as a chaotic struggle of dissatisfied peasant workers on the one hand, and the reluctance of Emperor Nicholas to make the necessary concessions and carry out economic reforms, on the other. This dissatisfaction of the people has lasted for a very long time. Finally, in October, there was a Revolution in which Lenin assumed power, but he did not have absolute support as he thought. Namely, Russia came out of the First World War. After the concessions to Germany, in terms of the territory, this did not affect the approval of the people, and shortly after the October Revolution a civil war broke out, between the "red" communists and "white" conservatives, the imperialists, the nationalists. Thus, the civil war postponed the establishment of a communist state.
The answer is B.