Randy Tsai is evaluating an AAA-rated corporate bond with exactly nine years remaining until maturity. The bond has a 4.5 percent semiannual coupon and is priced to yield 4.4 percent. As of today, the bond is callable at a price of 104 and putable at a price of 98 . The effective duration of this bond for a 75 basis point change in rates is closest to: A. 3.97. B. 5.61 . C. 5.71 . D. 6.18