Help me please :[ it’s the only question I have for a quiz and I get an 100 for the whole week or so

A hunter touches an infected animal’s blood, a farmer breathes the moist air exhaled by sick cows, contaminated meat is served at an outdoor market—these are a few of the ways pathogens spill over into the human population from infected animals or animal products.

Viruses only replicate inside living organisms, and adapt rapidly to a new host. One infection can spread to epidemic proportions in a matter of days.

The author organizes the selection by -

A. Illustrating what causes humans to catch viruses from animals

B. Comparing and contrasting the many different ways diseases are spread from human to human

C. encouraging people to properly care for the meat they eat

D. explaining how infection can spread from animals to humans and providing a solution to keep this from happening