rf恒定，有什么坏处呢

The Merton mol is useto prefault. It buil on seververy strong assumptions anits applicability is hamperepracticfficulties. Whiof the following statements es not correctly intify limiting assumptions or practicfficulties of using the mol? The mol relies on a simplistic capitstructure with only one issue. The asset value volatility cannot estimatebecause firm value es not tra. The mol assumes thes not pa coupon while most publicly trais coupon bt. The mol assumes a constant riskless interest rate. ANSWER: B This statement is incorrebecause the asset volatility crecovereiteratively from the equity volatility anmol prices. Other statements are correweaknesses of this mol. 在Monte模型里面我们用的波动率是公司V百分比形式的波动率吗

The Merton mol is useto prefault. It buil on seververy strong assumptions anits applicability is hamperepracticfficulties. Whiof the following statements es not correctly intify limiting assumptions or practicfficulties of using the mol? The mol relies on a simplistic capitstructure with only one issue. The asset value volatility cannot estimatebecause firm value es not tra. The mol assumes thes not pa coupon while most publicly trais coupon bt. The mol assumes a constant riskless interest rate. ANSWER: B This statement is incorrebecause the asset volatility crecovereiteratively from the equity volatility anmol prices. Other statements are correweaknesses of this mol. 1、老师，假设价格是对数，是不是蕴含的两个意思，价格连续，和大于零？ 2、另外，这里是沃顿推论四求p假设，不是沃顿模型的假设；我看了下PPT，沃顿里面没有波动率很定，波动率很定是BSM的假设；我感觉沃顿应该只是一种资产负债表的映射方法，这种方法用到BSM用来求， 和St等，所以如果题目问什么PLG,St的假设，直接往BSM上去想就完了？ 3、还有就是既然沃顿和BSM里面都说了，假设公司只有一种零息债；为啥沃顿的推论三还要讨论机构化债券的问题呢？ 4、沃顿里面有个假设“公司的股权、债务和资产可以很容易地在市场上交易。空头仓位没有限制。”资产可以交易想得通，就是求Vt，股权不就是求出来的嘛，债券也只需要一个到期面值F？ 5、莫顿的假设“均衡市场，风险补偿=miu-rf”，这个是用在哪里的啊？

B为什么错了呢，不是说有一个假设是公司资产可以tra么