Correct Option: D

Trichoderma harzianum has proved a useful microorganism for biological control of soil borne plant pathogens. Trichoderma harzianum is a fungus that is also used as a fungicide. It is used for foliar application, seed treatment and soil treatment for suppression of various disease causing fungal pathogens. Commercial biotechnological products such as 3 Tac have been useful for treatment of Botrytis, Fusarium, Penicillium sp. It is also used for manufacturing enzymes.