[单选题]Which is not an assumption of the specific factors model?qll答案窝(daanwo.com)-大学生作业答案及考资分享平台 Atwo goodsqll答案窝(daanwo.com)-大学生作业答案及考资分享平台 Bthree factors of productionqll答案窝(daanwo.com)-大学生作业答案及考资分享平台 Cperfect competition prevails in all marketsqll答案窝(daanwo.com)-大学生作业答案及考资分享平台 Dthree countries