MLO first discovered by

Answer: Option C

MLO was first discovered by Doi.
Mycoplasma-like organisms (MLO), pathogens of the plant yellows diseases, as a model of coevolution between prokaryotes, insects and plants.
Phytoplasmas, a large group of plant-pathogenic, phloem-inhabiting bacteria were discovered by Japanese scientist Doi in 1967.
They are transmitted from plant to plant by phloem-feeding insect hosts and cause a variety of symptoms and considerable damage in more than 1,000 plant species.