Ok, so maybe this isn't correct USMLE question style, but anyway:
The CDC stopped calling it "swine flu" because:
A) Rush Limbaugh said it's actually a terrorist weapon released into Mexico from where it would easily illegally enter the US
B) The pork industry is now in deep doodoo
C) Jewish and Muslim cultures don't like the word "swine" and want to call it "Mexican flu"
D) All of the above
E) B and C
F) none of the above
G) pigs can't fly