He wrote a letter ______ he explained what had happened in the accident.

A．what

B．which

C．where

D．how

在窗体上绘制一个名称为Commandl的命令按钮，然后编写如下程序：
Option Base 1
Private Sub Commandl_Click()
Dim c As Integer,d As Integer
d=0
c=6
x=Array(2，4，6，8，10，12)
Fori=1 To 6
1fx(i)＞c Then
d=d+x(i)
c=x(i)
Else
d=d-c
End If
Nexti
Print d
End Sub
程序运行后，如果单击命令按钮，则在窗体上输出的内容为( )。

A．10
B．16
C．12
D．20