问题详情

The reference to the "Gordian knot" (para. 5) suggests that the author thinks that
A．barter was inherently too slow
B．it was difficult to change the barter system to a monetary system
C．the economist Gordon deserves credit for introducing the monetary system
D．most people lack the skill to accurately determine the value of commodities请帮忙给出正确答案和分析，谢谢！