Answer:
A. Decomposers breaking down the material
Explanation:
Decomposition is the process in which decomposers such as bacteria break down the organic material in the atmosphere.
In the given image, decomposers breaking down the material shows carbon moving from the biosphere to the atmosphere because decomposers break down the dead organisms and in the process the carbon in the bodies of dead organism get back in to the atmosphere.
Hence, the correct answer is "A. Decomposers breaking down the material".
