GMAT Critical Reasoning (CR) | Ferguson’s Disease, a disorder in redwood trees that

Ferguson’s Disease, a disorder in redwood trees that is marked by a nutrient deficiency, is caused primarily by infestations of the fungus E. Coli but can also be a result of the use of fertilizers, which contain synthetic insecticides. Therefore, fertilizers should only be used on redwood trees when the soil surrounding them is proved to be rich in nutrients.
Which of the following, if true, most strengthens the above argument?

A. E. Coli causes trunk and branch decay that can cause redwood
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