设有如下程序： Private Sub Cimmandl_Click． Dim sum As Double, x As Double Sum=0 n =0 F

设有如下程序： Private Sub Cimmandl_Click． Dim sum As Double, x As Double Sum=0 n =0 For i =1 To 5 x =n/i n =n +1 sum =sum +x Next i End Sub 该程序通过For 循环来计算一个表达式的值，这个表达式是 A．1+1/2+2/3+3/4+4/5 B．1+1/2+1/3+1/4+1/5 C．1/2+2/3+3/4+4/5 D．1/2+1/3+1/4+1/5

请帮忙给出正确答案和分析，谢谢！