The information about how the flu virus spreads is included within the explicit message of the National Geographic video.
Answer: Option D
Explanation:
The video consists of a kid who coughs which causes the virus to spread from the cough to the glass of water which is later served to the other passengers. It later talks about how a flu virus goes into the body tends to spread, starting from the body to other people as well.
It also talks about the different types of flu, such as avian flu and swine flu with some subtle history of a flu attack which happened in the 17th century and resulted in the death more of the people.