A patent is an exclusive right given to an inventor for his or her invention. In other words, a patent is a monopoly right given to the inventor for the invention. A patent confers on the inventor the right to price and to sell the invention in any way he or she desires, in the United States, patents are granted by the Patent Office for 17 years. Although economists generally condemn monopoly as a form. of market organization since monopoly imposes costs on the economy, patents present a more subtle case for monopoly theory. Specifically, can patent monopolies be justified？

In general, economists complain about the costs of monopoly because they believe that the same industry could be organized competitively. A patent monopoly grant for 17 years presents a different problem. That is, the purpose of the patent system is to encourage invention. The issue is not monopoly versus competition but, more fundamentally, invention versus no invention. Is the world better off with the invention, even though it is monopolized for 17 years？ In other words, what are the costs and benefits of a patent？ Consider the simple case of a new consumer product with a positive demand, such as a camera utilizing a new exposure process. The costs of the patent monopoly are simply the deadweight costs of monopoly measured by the lost consumers' surplus from the 17-year patent monopoly. This cost must be assessed carefully in the context of an invention, however. What are the benefits of the patent system？ First, there is the increase in consumer well-being brought about immediately by a desirable invention. In 17 years, the patent monopoly ends, and a second source of benefits arises: The price of cameras will fall to a competitive level, and consumers will reap the benefits of the camera at a lower price. In sum, theory of monopoly helps us to assess the costs and benefits of the patent. One can quibble about patent monopolies, arguing, for example, that they are granted for too long a time. In the end, the patent system creates goods and services and technologies that did not previously exist. In this respect it is a valuable System for the economy. The patent system also underscores the importance of property rights to ideas as a source of economic growth and progress. The first paragraph mainly______. A．focuses on business monopoly B．tells us about the patent system in America C．discusses a special form. of market organization D．defines what a patent is and its function