MLO and spiroplasma are mostly

Answer: Option B

MLO and spiroplasma are mostly Phloem inhibiting.
A large group of plant-pathogenic, phloem-inhibiting bacteria was discovered by Japanese scientists in 1967. They are transmitted from plant to plant by phloem-feeding insect hosts and cause a variety of symptoms and considerable damage.
The spiroplasmas are mollicutes characterized by motility and helical morphology. They were discovered through studies on corn stunt and citrus stubborn diseases.
Mycoplasma-like organisms are generally considered to be somewhere between bacteria and viruses in size, shape and function.