Determine Whether the Following Transactions Involve Spot Exchange,contracts,or Vertical Integration

Essay

Determine whether the following transactions involve spot exchange,contracts,or vertical integration.
a.A major oil company refines gasoline from crude oil produced by oil wells that it owns.
b.Transcontinental,an interstate natural-gas pipeline,has a legal obligation to purchase a specified amount of gas per week from a well owned by Fred Smith in Enid,Oklahoma.
c.A cabinetmaker purchases a dozen wood screws from the local hardware store.
d.An electric utility purchases coal from an underground mine.