Last month, the Japanese government expressed their thanks for the aid they ______ from China.

A．receive

B．had received

C．have received

D．are receiving

在窗体上面一个命令按钮(其Name属性为Command1)，然后编写如下代码：
Option Base 1
Private Sub Coramandl_Click()
Dim a
s=0
a=Array(1,2,3,4)
j=1
For i=4 To 1 Step-1
s=s+a(i)*j
j=j*10
Next i
Print s
End Sub
运行上面的程序，单击命令按钮，其输出结果是______。

A．4221

B．1234

C．34

D．12