The supply-side analogue of these markets is rare today, though they used to be common in company towns. One variety of these arises in the sale of goods that are excludable but not rival. Because demand in these markets is not perfectly elastic, these markets produce less of a good than a perfectly-competing firm would, thus engendering their namesake "excess burden." While they are sometimes forbidden by antitrust law, legal examples include most public utilities as well as the former British 
The supply-side analogue of these markets is rare today, though they used to be common in company towns. One variety of these arises in the sale of goods that are excludable but not rival. Because demand in these markets is not perfectly elastic, these markets produce less of a good than a perfectly-competing firm would, thus engendering their namesake "excess burden." While they are sometimes forbidden by antitrust law, legal examples include most public utilities as well as the former British East India Company. For 10 points, identify this market that is characterized by a single firm being the only supplier in its industry.
The supply-side analogue of these markets is rare today, though they used to be common in company towns.
monopoly [accept word forms; do not accept "monopolistic competition" or "oligopoly" or "monopsony"]