Given a current flat yield curve for AAA bonds at 6% and the following bonds: Bond YTM Macauley's duration Quality Maturity Annual Current coupon price (paid annually) A AAA 5 years 6% $100 6% 4.46 B AAA 11 years 6% $100 6% 8.36 AAA 20 years 6% $100 6% 12.16 What is the portfolio duration of a barbell portfolio formed with an equal allocation in Bonds A and C? 8.36 12.50 8.31 11.00