计算π的近似值的一个公式如下:某人编写下面的程序用此公式计算并输出π的近似值: Private Sub Command1_Click() PI = 1 sign = 1 n = 20000 For k = 3 To n sign = -sign PI = PI + sign / k Next k Print PI * 4 End Sub 运行后发现结果为3.22751,显然,程序需要修改。下面修改方案中正确的是_______________。
A、把 For k = 3 To n 改为 For k = 1 To n
B、把 n = 20000 改为 n = 20000000
C、把 For k = 3 To n 改为 For k = 3 To n Step 2
D、把 PI = 1 改为 PI = 0