Which statement best captures the evolution of Indian federalism as revealed through 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, balanced by defined State domains and cooperative mechanisms, (b) Institutional mechanisms: (i) Finance Commission: Technical mediation of fiscal claims (41% devolution to States), (ii) GST Council: Cooperative taxation with weighted voting (Union 1/3, States 2/3), (iii) Inter-State Council: Policy dialogue on disputes/common interests, (iv) Zonal Councils: Regional cooperation on economic, social issues, (c) Judicial oversight: (i) SR Bommai (1994): Curbed Article 356 misuse, established floor test principle, (ii) Article 370 judgment (2023): Upheld Union power while directing democratic restoration, (iii) Water disputes cases: Balancing State rights with national interest, (d) Political negotiation: (i) Coalition era (1989-2014): Strengthened State bargaining power, (ii) GST implementation: Consensus-building across parties/States, (iii) Recent Governor-State tensions: Highlight need for clear conventions, (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), (f) 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.