I had to guess between A &D and got lucky

@Lucas, Great question. I think your initial interpretation is correct, minority is less than half, thus it is less than most and is best expressed as some. We can diagram the first sentence as: PA some-> SJ but notice that the natural language of this sentence suggests that if only a minority engage out of a sense of social justice, the majority must engage for other reasons, thus we can also diagram the first sentence as: PA most -> ~ SJ The invalid conclusion that follows can be diagrammed as: SJ some -> ~PA The argument in the answer choice (A) follows the exact same structure: S most -> ~PP PP some -> ~S Does this help? Let me know if have any further questions.

Great Explanation! A video would be helpful too.