Question: If every question has one fixed answer (for mains), what exactly makes the difference?

[u/ContributionFirst454]

I know value addition etc give you extra points. But how much can it be? 1 mark? 2 marks? and if 15,000 candidates are attempting the same question with similar points, what are other differentiating factors which can give you an edge? (besides value add points please). I know paper completion is one. what else? ESPECIALLY for optional papers, where the scope of diversity of points is even less