Answer: A. The fact that the sick person is a child helps underscore the point that anyone can spread the flu.
Explanation:
People are generally more likely to take notice of something if it affects children because that means it can affect anyone including those same children and there is a general consensus that children must be protected until they hit adulthood.
In using this poster, National Geographic wanted to invoke more feelings of fear, care and empathy in the subject because people watching would try to find out how to prevent the disease to reduce the number of children and by extension, adults getting it.
