Congo Basin Peatlands: The Congo Basin in Central Africa is home to the world's largest tropical peatland complex. This vast peatland stores an immense amount of carbon, estimated to be equivalent to about three years of global fossil fuel emissions. 

Importance of Peatlands: Peatlands are a critical carbon sink. They store more carbon than all the world's forests combined. When peatlands are drained or degraded, this stored carbon is released into the atmosphere, contributing to climate change. The Republic of Congo, the Democratic Republic of Cong and Indonesia are parties to the Brazzaville Declaration, aimed at protecting the Cuvette Centrale region in the Congo Basin, the world’s largest tropical peatlands, from unregulated land use and preventing its drainage and degradation. 

Other Options: 

• Amazon Basin: While the Amazon is known for its vast rainforests, it is not the primary location of the world's largest tropical peatland.

• Kikori Basin: The Kikori Basin is located in Papua New Guinea and contains significant peatlands, but not the largest tropical peatland complex.

• Rio de la Plata Basin: This basin in South America is primarily known for its grasslands and is not associated with major peatland areas.