National Fuel Allows Its Customers to Prepurchase Heating Oil in May

National Fuel allows its customers to prepurchase heating oil in May for the coming winter.National Fuel's customers who take advantage of the offer

A) are speculating that fuel prices will be higher in the future.
B) have purchased a form of call option for heating fuel.
C) are entering into a futures contract to offset the risk of higher fuel prices during the winter.
D) are purchasing a form of insurance against fuel shortages.