Which of the following best describes the contents of a flu vaccine? A.

deactivated particles of the flu virus

B.

medicine that activates if the flu virus becomes present in a host

C.

a virus that attacks the flu virus

D.

bacteria that distract the flu virus from attacking the host's cells

Answer: Option A) deactivated particles of the flu virus

Explanation:

A vaccine is a suspension of dead or wekeaned pathogen which may be injected into an organism to boost its immune system to fight against the same species, kind of pathogen or its toxins whenever such organism gets exposed to it in the near future.

For example: polio vaccine contains weakened viruses while flu vaccines contains deactivated particles of the flu virus.