9: In 1881, President James Garfield was shot as he entered a train station. Doctors tried to remove the bullet. However, they did not clean their hands or tools. They tended to him for about ten weeks before he died. Doctors found that he died from an infection rather than from the bullet. That discovery helped bring about some important changes in medicine.

How does paragraph 9 fit into the overall structure of the article?

A. It shows that studying an error led to progress in medicine.

B.
It shows that doctors did not need to clean their hands or tools.

C.
It tells what happened to President Garfield after he was shot.

D.
It shows that there were no advancements in medicine before 1881.