Barack Obama, who came into _________ power on January 20, 2009, was awarded _________2009 Nobel Peace Prize.[ ]

A. the; the

B. the; /    

C. /; the

D. /; /

绝对优势理论由（）提出，它以（）的绝对差异论证国际贸易的基础。

A.亚当斯密；劳动成本

B.亚当斯密；资本、劳动、土地

C.马克思；劳动成本

D.马克思；国际价值