A stock priced at $ 20 has an 80 percent probability of moving up and a 20 percent probability of moving down. If it moves up, it increases by a factor of 1.05. If it moves down, it decreases by a factor of 1/1.05. What is the expected stock price after two successive periods（）

A. $ 20.05.

B. $ 22.05.

C. $ 21.24.

使用VC6打开考生文件夹下的工程test31_1，此工程包含一个源程序文件test31_1.cpp，但该程序运行有问题，请改正程序中的错误，使该程序的输出结果为：
max(1，2)＝2
max(1，4)＝4
源程序文件test31_1.cpp清单如下：
#include ＜iostream.h＞
/***************** found *****************/
template class T
T GetMax (T a, T b)

T result;
result = (a>b)a:b;
return result;

void main()

int i=1, j=2;
double k=4;
cout＜＜"max("＜＜i＜＜","＜＜j＜＜")="＜＜GetMax(i,j)＜＜end1;
/***************** found *****************/
cout＜＜"max("＜＜i＜＜","＜＜k＜＜")="＜＜GetMax(i,k)＜＜end1;
/***************** found *****************/
return 0;