According to Application 4

According to Application 4.2, "The $4 Summer of 2008,"

A) the price of gasoline and milk hit $4 a gallon during the summer of 2008.
B) dairy farmers had to raise their prices of milk because the high cost of gasoline drove up the price of corn.
C) we knew an oil-based energy problem was looming but did not anticipate the severity and suddenness of the rise in oil and gasoline prices.
D) all of the above.