The correct answer is option D, that is, it will increase the amount of carbon in the soil and increase the amount of carbon dioxide discharged by decomposers.
One of the ways to manage the garden is to utilize mulch, the mulch minimizes the contact between the soil and the organic matter so that the species will consume more time to dissociate it. The mulch will decompose and its nutrients will be discharged to the soil, however, it takes place very gradually, and enhances the organic matter in the soil.
If the mulch is left in the garden for a year, then the soil will be conserved and supplied with nutrients and this process will retain carbon in that garden. The sources of mulch can be leaves, grass, straw, or composted garden waste.
