How does the following sentence contribute to the development of the main idea in the article? This was strong evidence that the innate immune system is responsible for putting farm microbes to good use in the body.

A. It shows the connection between the Amish immune systems and their environment.
B. It develops the idea that the genes you are born with will determine if you get asthma or not.
C. It proves that the Amish are the healthiest group of Americans.
D. It gives an example of how farm microbes can hurt children.