NO.PZ2020021204000024
问题如下：
In an upward-sloping yield curve environment where interest rates are above 6%, what types of bonds tend to be cheapest to deliver?
选项：
解释：
Low coupon long-maturity bonds will tend to be cheapest to deliver.
为什么是低票息的债会更容易交割，长久期我大概明白
