The mass struggle mentioned in the question is most likely referring to movements against military dictatorships that have occurred in various parts of the world, where the masses have fought for democracy and freedom.
Step 1: Identifying the mass struggle.
- Mass struggles were often directed against military regimes, especially in countries with long histories of military rule.
- Socialism and communism, while often part of political struggles, were not necessarily the targets in this case.
Step 2: Conclusion.
The correct answer is (B) Military dictatorship, which was the focus of many mass movements.