The correct answer is A. Mongols and Vikings.
Vikings and Mongols is where Russia traced their original settlement.
Russia history started at the time of establishment for the Kievan Rus'.
Due to invasion of mongols, Kievan Rus' was disintegrated. For the combination of war-weariness, discontent with autocratic government system and economic breakdown triggered to Russian revolution.
They lost their superpower status and retained their nuclear arsenal.