public static double ComputePrice(double S, double K, double r, double sigma, double T, double t)
 {
     // ((LN(J10/$J$2))+($J$3+(0,5*($J$4^2)))*(J11-$J$5))/($J$4*RAIZ(J11-$J$5))
     return(S *
            StandardNormalDistribution.NormSDist(D1(S, K, r, sigma, T, t))
            - K * (System.Math.Exp(-r * (T - t)) *
                   StandardNormalDistribution.NormSDist(D2(S, K, r, sigma, T, t))));
 }