Which statement best captures the evolution of Indian federalism as reflected in case studies like Article 370 abrogation, GST Council functioning, SR Bommai judgment, and Finance Commission recommendations?

Indian federalism evolution (case studies synthesis): (a) Constitutional design: Quasi-federal with unitary bias (residuary powers with Union, Emergency provisions, All India Services) to ensure national unity in diverse post-Partition context, (b) Institutional mechanisms: Finance Commission (fiscal devolution), GST Council (cooperative taxation), Inter-State Council (policy dialogue), Zonal Councils (regional cooperation) enable Centre-State coordination, (c) Judicial oversight: SR Bommai (curbing Article 356 misuse), Article 370 judgment (interpreting temporary provisions), water disputes cases (balancing State rights with national interest) ensure constitutional balance, (d) Political negotiation: Coalition era (1989-2014) strengthened State bargaining power; GST implementation required consensus-building across parties/States, (e) Adaptive flexibility: Federalism evolves through amendments (101st-GST, 105th-State OBC lists), judicial interpretation, administrative practice to address contemporary challenges (digital governance, climate change, identity politics). Core principle: Unity in diversity — strong Centre for national integrity, autonomous States for regional expression, cooperative mechanisms for shared governance. Essential for UPSC Mains conceptual understanding.