The first 6-year U.S. Treasury bond with a face value of $100 pays a coupon of 9%. The reported yield to maturity is 5%. The second 6-year U.S. Treasury bond with a face value of $100 pays a coupon of 6%. The reported yield to maturity is 5%. Which bond has a shorter duration and a lower volatility? O a. the first U.S. Treasury bond, 5.23 years of duration and 4.98% of volatility. O b. the first U.S. Treasury bond, 4.99 years of duration and 4.75% of volatility. O c. the second U.S. Treasury bond, 5.23 years of duration and 4.75% of volatility. O d. the second U.S. Treasury bond, 4.99 years of duration and 4.98% of volatility