What would be the impact of a virus that infected the Midwestern corn crop?

a. Price of corn increases and the price of wheat decreases
b. Price of corn decreases and the quantity of wheat increases
c. Quantities of corn and wheat increase
d. Quantity of corn decreases and the price of wheat increases

d. Quantity of corn decreases and the price of wheat increases.
Corn Market: The virus is represented by a shift back in the supply curve, which increases the price and decreases the quantity of corn - rule out answers b and c. Wheat Market: Because corn and wheat are substitutes, the increase in the price of corn would shift the demand for wheat out (people substitute from corn to wheat). An increase in demand for wheat would increase both the quantity and price of wheat.