(a)[4]
The article mentions concentration ratios. Explain what a concentration ratio means and how it is worked out.
(b)[4]
Explain, with an example, whether the article is right to say that neither the producer nor the consumer pays for negative externalities.
(c)[4]
Apart from negative externalities, describe two reasons why the article argues that increased concentration in an industry may not improve consumer welfare.
(d)[8]
The article claims that monopolies are tolerated because they are efficient. Assess, with the help of a diagram, whether economic theory supports the idea that monopolies are efficient.