You are managing a portfolio of $1 million, your target duration is 12 years, and you can choose from two bonds; a zero-coupon bond with a maturity of 5 years, and perpetuity, each currently yielding 5%. To immunize the interest rate risk, you should purchase of perpetuity today. $ A $437,500 B) $125,000 C) $875,000 (D) $562,500