Which of the following markets has a barrier to entry? A. There are already many fast food restaurants in the City of Buffalo. B. Stan's Garbage Company runs the only trash collection service in town. C. Crystal develops a new product and patents it. D. Gold can only be mined in certain places in the world.

C. Crystal develops a new product and patents it.

Explanation:

A Patent is one of the ways that a monopoly can be formed in an industry. A Patent is a government issued guarantee that other entities should not tamper with the product that was patented unless they get permission from the patentee to do so.

Patents in the United States usually last for 20 years and in that time only the people who patented it may use it. This is a Government enforced barrier to entry as other companies cannot make the product in question thereby creating a monopoly for the people that did patent it.

the answer is true

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