The 'CARBON SINK' concept in international environmental law refers to:

1. A CARBON SINK is a natural or artificial reservoir that ABSORBS MORE CARBON than it RELEASES — net negative emissions. 2. Major carbon sinks: (i) FORESTS (photosynthesis); (ii) OCEANS (largest sink, dissolved CO2); (iii) SOIL (organic matter accumulation). 4. Under the UNFCCC 1992 Article 4 and Kyoto Protocol 1997, countries can count carbon absorbed by their sinks toward emission reduction commitments. 5. REDD+ (Reducing Emissions from Deforestation and forest Degradation) — UNFCCC framework allowing developing countries to receive financial incentives for protecting forests as carbon sinks. 6. India's NDC commits to creating an additional carbon sink of 2.5-3 billion tonnes CO2 equivalent through additional forest and tree cover by 2030. 7. Hence option B is correct. _Source: EPA 1986 / Constitution / International Conventions — UNFCCC 1992 Article 4; Kyoto Protocol 1997; REDD+ Mechanism_