The correct answer is option d, that is, there is a forest where many trees are absorbing carbon.
The tendency of the forests to absorb carbon dioxide is associated with numerous elements, that is, how the forests are managed, the age of the trees, the nutrient content of the soil, the local environment, and the level of precipitation.
It has been found that the established forests, that is, found from the boreal forests in the north to the tropical rainforests in the south, captivates about 8.8 billion tonnes of carbon dioxide in a year.