问题如下：
Which term structure model can be calibrated to closely fit an observed yield ciuve?
选项：
A.The Ho-Lee Model
B.The Vasicek Model
C.The Cox-Ingersoll-Ross Model
解释：
A is correct.
The Ho-Lee model is arbitrage-free and can be calibrated to closely match the observed term structure.
此题与：NO.PZ2018123101000017 一致，同时出现在课后练习中，建议修订
