Answer:
There is no diagram but
It would be A if you were looking at the endoplasmic reticulum (ER).
It would be B if you were looking at a mitochondrion.
I do not remember what C is, so if it is not the ER, Golgi apparatus, or the mitochondrion, it is most likely C.
It would be D if you were looking at a Golgi apparatus
Less genetic variation in the inheritance of traits causes a crops ability to be more prone to disease because there are less alleles immune to disease in the genetic pool