30. Which of the following characterises the scientific publishing model?

【答案】[D]The few feed on the many.

【解析】第六段最后提出，“ In some ways the scientific publishing model resembles the economy of the social internet: labour is provided free in exchange for the hope of status, while huge profits are made by a few big firms who run the market places.”，意为“在某些方面，科学出版模式类似于社会互联网的经济:劳动力是免费提供的，以换取地位，而巨额利润则由少数经营市场的大公司赚取”，意思是，少数公司榨取了大众的免费劳动，因此获利，故答案为 D。