问题如下图：
选项：
A. 
B. 
C. 
请问C错在哪里
NO.PZ2015121810000027 问题如下 The prices of one-perio refault-free government bon are likely to most sensitive to changes in: A.investors’ inflation expectations. B.the expectevolatility of economic growth. C.the covarianbetween investors’ inter-temporrates of substitution anthe expectefuture prices of the bon. B is correct.Only changes in fault-free reinterest rates will affethe priof real, fault-free bon. The average level of fault-free reinterest rates is positively relateto the volatility of economic growth in the economy; thus, changes in the expectevolatility of economic growth woullikely leto changes in refault-free reinterest rates, whiin turn woulaffethe prices of real, fault-free government bon. 考点scount Rate on Refault-free Bon解析排除法A ，rebon 不会受到通货膨胀的影响，nominbon 才会B ，volatility of economic growth 影响分母 l，即 refault-free interest rate，所以 B 正确C ，one-perio的债券价格不受 covarian的影响，因为 one-periofault free bon的 covariance=0。只有多期债券才会受covarian影响 我有点不太明白，这个是定义吗，为什么说real就是考虑了通货膨胀因素呢？
NO.PZ2015121810000027 问题如下 The prices of one-perio refault-free government bon are likely to most sensitive to changes in: A.investors’ inflation expectations. B.the expectevolatility of economic growth. C.the covarianbetween investors’ inter-temporrates of substitution anthe expectefuture prices of the bon. B is correct.Only changes in fault-free reinterest rates will affethe priof real, fault-free bon. The average level of fault-free reinterest rates is positively relateto the volatility of economic growth in the economy; thus, changes in the expectevolatility of economic growth woullikely leto changes in refault-free reinterest rates, whiin turn woulaffethe prices of real, fault-free government bon. 考点scount Rate on Refault-free Bon解析排除法rebon不会受到通货膨胀的影响，nominbon才会。B，volatility of economic growth影响分母l，即refault-free interest rate，所以B正确C，one-perio债券价格不受covariance的影响，因为one-periofault free boncovariance=0。只有多期债券才会受covariance影响。 这里可不可以直接总结为单期情况下，价格就是替代率，替代率只会受到经济好坏的影响，所以选未来经济的波动率
NO.PZ2015121810000027 其中inter-temporrate 与maginutility关系还是不太明白
NO.PZ2015121810000027 老师，请问如何准确理解Refault-free债券价格？公式是pri= risk neutrPV + covariance. 请问如果Covariance是风险的折现，那这个公式不就变成风险资产了的定价了？“无风险 + 风险溢价” 另外，老师讲的refault interest rate不是仅仅补偿人的不耐情绪吗？请问当经济volatile的时候，到底是经济波动本身的风险导致折现率变高，还是人的情绪变化导致折现率变高？这里到底有没有风险的存在？谢谢
为什么growth volatility越大，l越大呢？是讲义中哪句话？ 我理解的讲义中只是说未来growth预期越大，l越大，但是growth越大和growth volatitlity越大是两码事。。
