"Climate Action Tracker" which monitors the emission reduction pledges of different countries is a :

Answer: (a) Database created by coalition of research organisations

The Climate Action Tracker is an independent analysis run by research groups (Climate Analytics and NewClimate Institute).

The idea

Under the Paris Agreement each country sets its own target (its NDC). Nobody inside the UN system gives marks to an individual country. Independent research groups fill that gap: they compare each pledge with the 1.5°C goal and publish a rating.

Country announces a pledge → UNFCCC records pledges, reviews reports and assesses collective progress → Independent researchers add up all pledges → They work out the warming that would follow → The gap from 1.5°C becomes public pressure

Why the others are wrong

(b) The IPCC does no monitoring of countries. It reviews published research and writes assessment reports.

The trap

Anything that tracks country pledges sounds official. Many trackers are independent research consortia.

Elimination technique

Options (b), (c) and (d) each make the tracker a wing, committee or agency of a UN body. Such parentage claims are usually false in Environment PYQs. The one option without a UN parent is the answer.

Also know

Who publishes what: IPCC (set up in 1988 by WMO and UNEP) = assessment reports on the science; UNFCCC = the Global Stocktake every five years; UNEP = Emissions Gap Report and Adaptation Gap Report; Germanwatch = Climate Change Performance Index. The Climate Action Tracker is run by Climate Analytics and the NewClimate Institute.