Illustrate the following with supply and demand curves: 

a. In November 2017, Leonardo DaVinci’s oil painting Salvator Mundi was sold at Christie’s Auction House in New York for a record-shattering $450.3 million. 

b. In July 2018, hogs in the United States were selling for 70 cents per pound, down from 81 cents per pound a year before. This was primarily due to the fact that supply had increased during the period. 

c. In 2017, the demand for organic produce increased by 5.3 percent from the previous year, while the number of U.S. certified organic farms increased by 13 percent. The overall result was a drop in the average price of organic produce and an increase in the quantity of organic produce sold.