【正确答案】 C

【答案解析】[听力原文]
   Up to half of the food the world produces is never eaten. It is instead thrown away. Experts say food is wasted in both rich and poor countries, but for different reasons.
   In poor countries, food is usually lost while it is still in the field or during storage and transportation. That is because food producers there are inefficient. These businesses are unable to operate effectively without wasting materials, time or energy. Once food is sold in developing countries, people usually eat everything they buy. However, people in the United States and other developed countries throw away as much as half of the food they purchase. The British researcher called this custom "a disgrace." One way to solve the problem of wasted food is to take steps to persuade people to stop buying so much food in the first place.
   What do we know about food in developed countries?