Suppose that the risk-free yield curve is flat at 8% (with continuous compounding). The payoff from a derivative occurs in four years. It is equal to the five-year rate minus the two-year rate at this time, applied to a principal of $100 with both rates being continuously compounded. (The payoff can be positive or negative.) Calculate the value of the derivative. Assume that the volatility for all rates is 25%. What difference does it make if the payoff occurs in five years instead of four years? Assume all rates are perfectly correlated.