Cities like San Francisco and New York that require a driver to buy a city-issued taxi medallion before the driver can legally operate a taxi are shifting the supply curve for taxis to the left relative to where it would be without the requirement for a medallion.

a. Briefly explain why the supply curve for taxi rides shifts to the left. What is the effect on the market price of taxi rides from the medallion requirement?

b. A news article made the following two points: (1) In 2010, medallions in San Francisco were selling for \($250,000,\) and (2) no medallions were sold between 2016 and 2021. Why would taxi medallions have been worth \($250,000\) in 2010? Why was it apparently impossible to sell them at any price between 2016 and 2021?