To calculate the value of the bond in period t+1 when the interest rate falls to 4%, we can use the present value formula for a bond:
Bond Value = Coupon Payment / (1 + Interest Rate) + Coupon Payment / (1 + Interest Rate)^2 + ... + Coupon Payment / (1 + Interest Rate)^n + Face Value / (1 + Interest Rate)^n
In this case, the coupon payment is 50, the face value is 1000, the interest rate in period t is 5%, and the interest rate in period t+1 is 4%. The bond matures in 10 years.
Let's calculate the bond value in period t+1:
Bond Value = 50 / (1 + 0.04) + 50 / (1 + 0.04)^2 + ... + 50 / (1 + 0.04)^10 + 1000 / (1 + 0.04)^10
Using a calculator, the bond value in period t+1 is approximately 1081. Therefore, the correct answer is 1081.