【正确答案】 D

【答案解析】[听力原文]
   OPEC, the Organization of Petroleum Exporting Countries agreed this week to increase oil production. The increase is aimed at lowering oil prices, which went up after OPEC and several other nations cut production last year. The OPEC agreement is expected to add 1.7 million barrels of oil a day. That would increase oil supplies more than seven percent. Nine of the eleven OPEC members agreed to the increase at a meeting in Vienna. Iraq is not involved in the plan because of its separate United Nations off-for-food program. Iran at first refused to take part in the increase to protest American pressure on OPEC. However, later Iran said it would also agree to increase production. Iran is the second largest OPEC producer, after Saudi Arabia. The United States is OPEC's largest market.
   Why did the OPEC want to increase oil production this week?
细节题。此题问OPEC增加石油产量的原因。由画线句可知，目的是为了降低石油价格。因此D是正确选项。