A、$20 000 every year. B、$ 5 100 every two years. C、$ 510 every year. D、$ 200 every two years. D

A conflict is forming on the streets of New York City between legal and illegal food trucks and carts. The city grants 5 100 food vending permits every two years. The permit is issued by the Department of Health and Mental Hygiene. Most of the permit holders pay $200 to renew their permit every two years. Some permit holders rent their license, or permit, for a profit. Some cart or truck operators pay more than $20 000 for a food vending permit. Because there is a greater demand than supply of permits, a black market for the licenses has emerged. It is reported that transferring or renting these permits to another vendor is illegal. But many vendors have turned to this illegal black market for permits. The vendors say getting a cart or truck permit can take 10 to 15 years. Some vendors work the street unlicensed.
3. How much should the permit holders pay to renew the permit?
4. Why has a black market for the licenses emerged?