Read the excerpt from the supporting text "Disease Central" in When Birds Get Flu by John DiConsiglio.

In 1958, scientists at the CDC made their first trip overseas. A team went to Southeast Asia to respond to an epidemic of smallpox and cholera.

The author uses this passage to help the reader focus on

A .why Dr. Dowell is in Thailand.
B .why epidemics are dangerous.
C .why scientists work for the CDC.
D .why the CDC was formed.