Originally the Cancun meeting aimed at ______ A: raising tariffs and agricultural subsidies in the developed countries B: extending the benefits of freer trade and markets to poorer countries C: demanding continued support from Washington D: United State' commitment to a clear phasing out of its cotton subsidies

以下哪个陈述最能体现“天下没有免费的午餐”这句谚语所代表的原理?____ A: Melissa只有带着妹妹一起,才能去听音乐会 B: Greg忍饥挨饿,无家可归 C: Brian得先修好自行车轮胎,才能骑着去上课 D: Kendra必须决定春假期间是去Colorado还是Cancun