If individual countries that are members of OPEC exceed their production quotas, the amount of oil supplied to the world oil market increases. This oversupply of oil leads to a surplus, which puts downward pressure on prices due to the basic economic principle of supply and demand. When supply exceeds demand, prices tend to fall. So, when the amount of oil supplied to the world oil market increases, the price of oil decreases due to oversupply. Therefore, the correct answer is D. decreases; increases.
