我不明白这道题为何选C，如果OAS大，相当于spread大，那应该价格低啊-如果价格跟低OAS的bond一样，那说明被高估了阿？问题如下图：
选项：
A. 
B. 
C. 
解释：
NO.PZ201602270200002101 问题如下 1. Baseon Exhibit 1, Rayes woulmost likely conclu threlative to Bon#1, Bon#2 is: A.overprice B.fairly price C.unrprice C is correct.The option-austespre(OAS) is the constant spreaeto all the one-perioforwarrates thmakes the arbitrage-free value of a risky bonequto its market price. The Oapproais often useto assess bonrelative values. If two bon have the same characteristiancret quality, they shoulhave the same OAS. If this is not the case, the bonwith the largest O(i.e., Bon#2) is likely to unrprice(cheap) relative to the bonwith the smallest O(Bon#1). 如果折现率高价格就低的话，他们的现金流是一样的？我不太理解什么是一样的characteristics。谢谢老师
NO.PZ201602270200002101 callable bon分母不是r-oas吗，oas越大，分母越小，bonri更高，更overprice
