The correct option is D Produced by the process of mineralisation
The rate of catabolic action of different complex substances in the detritus is different. This produces two substances in the form of humus and inorganic nutrients through the process of humification and mineralisation respectively. Humification is the process by which simplified detritus gets converted into a dark coloured formless substance that is rich in cellulose, and phenolic compounds like lignin, tannins, resin, etc. This substance is known as humus. Its specific character is that it is highly resistant to microbial action and so,it undergoes extremely slow decomposition. It is slightly acidic, colloidal and functions as a huge reservoir of nutrients. Mineralisation on the other hand is the other aspect of catabolism where the nutrients present in the detritus matter is released into the soil and made available for plants to reuse.