Suppose this is the market of oil workers in Texas. Assume that coal is a substitute for oil. Draw a supply and demand diagram to illustrate what would be the effect of each of the following events in the equilibrium wage and equilibrium quantity of oil workers:
a. The price of oil rises.
b. New oil-drilling equipment is invented that is cheap and requires few workers to run.
c. Several major companies that do not drill oil open factories in Texas, offering many well-paid jobs outside the oil industry.