Please help!!
Greyhounds are dogs with long, powerful legs and slim bodies that make them very fast runners. Which of the following best describes how humans were able to engineer this breed of dog?
A). For many generations, these dogs were allowed to run freely in large, open fields.
B). Dogs that were slower than others were given exercise and trained to run fast.
C). Over many years, all the dogs were fed diets high in protein and vitamins.
D). In every generation, only those dogs with the desired traits were allowed to reproduce.