The Khasi Hills Community REDD+ Project holds the distinction of being India’s very first REDD+ (Reducing Emissions from Deforestation and Forest Degradation) project.

It is certified under the Plan Vivo Standard, a globally recognized, fair-trade-styled framework specifically designed for community-based forest carbon projects. The project is located in the East Khasi Hills District of Meghalaya, situated along the Umiam River watershed. It is managed by a federation of 10 indigenous Khasi tribal kingdoms (comprising over 60 local communities), locally known as a Synjuk. The project utilizes REDD+ to protect existing dense forests and ancient indigenous sacred groves, and Assisted Natural Regeneration (ANR) to restore degraded open forests.

Uttarakhand REDD+ project is incorrect as, while Uttarakhand has engaged in REDD+ readiness and pilot initiatives, it does not hold the title of the first Plan Vivo certified project in India.

ICFRE-ICIMOD Transboundary REDD+ project in North-Eastern Himalayas is incorrect. This is a broader transboundary initiative focused on capacity building and REDD+ readiness across Himalayan countries, rather than a specific, first-of-its-kind Plan Vivo certified community project in India.

Sikkim Mamley Kamrang Community REDD+ project is incorrect. Although Sikkim has undertaken significant forest conservation and climate mitigation efforts, the Khasi Hills project is officially recognized as India's first Plan Vivo certified REDD+ project.

Therefore, the correct option is C.