Answer:
The correct answer is letter "B": A change in the price of oil.
Explanation:
The supply curve for any good or service responds in front of changes in price. According to the supply law, if the price of a good or service increases so will the quantity supplied moving the supply law to the right. If the price of the good decreases so will the quantity supplied moving the supply curve to the left. The price-quantity supplied relationship is directly proportional.