How can an oligopoly cause market failure​

Market failure due to Oligopoly

Inefficiency, instability and indeterminacy brought about by oligopoly may result in a market crash. The firm's supremacy is established as the capacity is established more and more, but little is produced in order to create artificial barrier to entry.

answer: a. the kind of population living in your neighbourhood.

the census explorer data tool by the us census bureau allows the user to zoom in on any neighbourhood within the united states and find the kind of people residing in that by race and age.  

the tool needs to needs to be used twice – once in order to find what type of people reside in a neighbourhood, and then to see the age groups of the people in the same neighbourhood.