Don Ondrus, a fixed income analyst with Quantitative Capital Corp., is seeking to measure the interest rate sensitivity of a bond. The bond in question is an 8-year maturity corporate bond with a 7.5 percent semiannual coupon and a par value of $1,000. The bond is currently yielding 7.2 percent and is callable at 104 percent of par. The effective duration of the bond for a 50 basis point change in interest rates is closest to: A. 4.00 . B. 4.58. C. 5.09 . D. 5.96