The correct option is D Both souring and the ripening processes
In cheese manufacture, the microorganisms are important for both souring and the ripening processes. In cheese making, the curdling stage relies on lactic acid bacteria. The carbohydrates present in the milk are fermented by these bacteria, releasing lactic acid in the process which makes sour (fermented milk or cultured milk). Cheese maturation is the method of cheese ripening that takes place after cheese souring.