Answer:
Agglomeration economies.
Explanation:
Agglomeration economies, also known as external economies of scale, consist of the advantages of focusing output and residence in some specific areas. If some particular area produces certain kinds of goods, all firms can take advantage of many factors like networks for the supply of goods, workers, transport, and a proper infrastructure for the industry.
When there are not many sellers of a item the price of the item goes up because not many people have that item or sell it and the fewer the people that sell that item the more money the people make that have it and it makes it harder to get.
