The reason why some nonindustrial societies promote specialization is that __

C。本题出题点在因果关系及转折处。根据题干信息词promote specialization将答案锁定在文章第三段，此段说明为什么在有些部落社会中会出现技术专业化。本段第三句说“They don’t specialize，as one might suppose．because certain raw materials happen to be available near particular village．”，可见A错误；第五句说“Everyone knows how to make pots，but not everybody does S0．”，可见B错误；最后一句“Specialization contributes to keeping the peace，although it has not prevented inter-village warfare．”，可见D错误；本段倒数第二句说“Such specialization promotes Wade，which is the first step in creating an alliance with enemy villages．”，即这种专业化可以促进贸易，这是与敌对村落结盟的第一步。因此C为正确答案。