Answer:b pollution from a factory on the health of people in the vicinity of the factory.
Explanation:
Externality refers to industrial impacts
On other parties which is usually not reported when they sell their products, there are so many things that can happen on lower levels that never get reported publicly for everyone one to know.
These may be bad things contributed by the industry or good things contributing to the industry but because they may not be important for marketing purposes they may never be mentioned or because they may have an impact on the success of that industry or because they are not seen as crucial things that need to be reported or be revealed they are always left out.
