NO.PZ2021103102000032
问题如下：
Which of the following statements about commodity investing is invalid?
选项：
A. In backwardation market, the commodity’s forward curve is downward sloping and there is high convenience yield.
B. In contango market, the commodity’s forward curve is downward sloping and there is little or no convenience yield.
C. In contango market, the commodity’s forward curve is upward sloping and there is little or no convenience yield.
解释：
期货升水(contango)市场中，现货价格低于期货价格，远期价格曲线向上倾斜，便利收益(convenience yield)很少或没有。 期货贴水(backwardation)市场中,是相反的情况，即现货价格高于期货价格，远期价格曲线向下倾斜，便利收益率较高。
可以再解释一下怎么得出关于convenience yield 高或低的这一结论的吗
