The White Leghorn Hen Is Prolific at Egg Laying, but Not

The white leghorn hen is prolific at egg laying, but not good for meat production and now produces almost all of the eggs in the U.S. This points to a global trend where

A) genetic variety is being expanded through genetic engineering.
B) a single variety of farm animal cannot face extinction through a disease outbreak.
C) animals bred for maximum production are not performing as anticipated.
D) farmers are being subsidized not to keep white leghorn hens.
E) the eggs and sperm of domesticated animal varieties are being banked for preservation.