A portfolio manager has a bond portfolio worth $10 million. The duration of the portfolio is 3.1 years and they are corporate bonds. The portfolio manager believes that the interest rates are going to drop but not certain about the magnitude. She decides to raise the duration of her portfolio to 5. What does she need to do to get the intended duration? O Sell Treasury Bond Futures O Buy Treasury Bills Futures O Buy more corporate bonds with similar duration O Do nothing 1804