Answer:Decrease in supply.
Explanation: Supply is the amount of goods and services which an individual is willing and ready to purchase at a given price. The invention of a new technology which makes gasoline production less costly will lead to a decrease in price. Producers reduces supply when there's a decrease in price and increase supply when there's an increase in price. Also, the destruction of several oil fields means that there would be a reduction in the supply of oil in the economy. Since oil fields have been destroyed, it will have a negative effect on supply.