Explanation:

All statements are correct.

Carbon Credits

• Carbon credits, or carbon offsets, refer to carbon emissions reductions or removals, measured in tonnes of carbon dioxide equivalent (tCO2e). 

• The concept of carbon credit, introduced in the Kyoto Protocol, 1997 and reinforced by the Paris Agreement, 2015 aims to reduce greenhouse gasses (GHG) emissions through carbon trading.

• Each carbon credit permits the emission of one tonne of CO2 or its equivalent.

• These credits are generated by projects that absorb or reduce carbon emissions and are certified by international bodies like the Verified Carbon Standard (VCS) and the Gold Standard. 

Hence option 3rd is correct.