47) Suppose we have a 30-year MBS with a modified duration of 3.00 years priced at $107.62. If interest rates decline by 100bps the price increases to $110.94 and if interest rates increase by 100bps the price falls to $103.41. What is the effective duration of this security? a) 3.50 years b) 4.25 years c) 3.10 years