In the context of C02 emission and Global Warming, what is the name of a market driven device under the UNFCC that allows developing countries to get funds/incentives from the developed countries to adopt, better technologies that reduce greenhouse gas emissions ?

The Clean Development Mechanism (CDM) is a market-based mechanism established under the Kyoto Protocol that allows Annex B (developed) countries to finance emission-reduction projects in developing countries and, in return, earn tradable Certified Emission Reduction (CER) credits (each equal to one tonne CO2) that count toward Kyoto targets [1]. The UNFCCC identifies the CDM as one of the Kyoto “mechanisms” designed to stimulate sustainable development, technology transfer and cost‑effective greenhouse‑gas reductions by enabling investment flows from developed to developing countries [2]. This structure — financing, incentives and tradable credits — matches the description in the question, so the correct answer is the Clean Development Mechanism.

Sources

1. [1] Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 21: Sustainable Development and Climate Change > SUSTAINABLE DEVELOPMENT GOALS > p. 599
2. [2] https://unfccc.int/process/the-kyoto-protocol/mechanisms