Consider the market for taxi service in Washington, DC. Use demand-supply analysis to explain the effects (i.e., increase or decrease) on the equilibrium price and quantity from the following (you may consider each case separately; and assumes that only one side of the market is affected; however, it is much more interesting to consider situations where both the supply and demand curve change simultaneously.):

a. Bus drives go on strike.

b. Taxi drivers must pass a competency test, and a third of all drivers fail.

c. Gasoline prices increase

d. Half of the downtown parking lots are converted to office building.