问题
单项选择题
Gold which is 10 Karats in proportion ______ in the U.S.
A．represents the highest grade of gold
B．cannot be sold
C．never carries a Karat quality mark
D．represents the lowest-grade gold marketable
答案
参考答案：D
解析：[分析] 细节题型。 见文中：The lowest Karat gold that can be marketed in the United States is 10-Karat gold．能够在美国市场上交易的黄金最低含金量不能低于10K。因此选项D；“10K，的黄金是美国能够上市的最低级别的黄金。”是答案。