Answer the following questions. a. The mean change in the value of a portfolio of trading assets has been estimated to be 0 with a standard deviation of 20 percent. Yield changes are assumed to be normally distributed. What is the maximum yield change expected if a 95 percent confidence (one-tailed) limit is used? b. City bank has six-year zero coupon bonds with a total face value of $20 million. The current market yield on the bonds is 10 percent. What is the daily value at risk (VaR) of this bond portfolio