Crop Sunflowers Are Attacked by Many Fungal Pathogens, Such as Downy

Crop sunflowers are attacked by many fungal pathogens, such as downy mildew and Sclerotinia, resulting in economic losses of millions of dollars per year. What genes would be best to target for the development of new fungus-killing crop treatments (fungicides) ?

A) Genes encoding chitin proteins that are shared by downy mildew and Sclerotinia, but absent in sunflower and humans.
B) Genes encoding growth proteins that are shared by downy mildew, Sclerotinia, and sunflower, but absent in humans.
C) Genes encoding metabolite proteins that are shared by downy mildew, Sclerotinia, and humans, but absent in sunflower.
D) Genes encoding basic development proteins that are shared by downy mildew, Sclerotinia, sunflower, and humans.