单项选择题

下列程序运行后的输出结果是
Private Sub Command1_Click()
For k=3 To 1 Step-1
x=String(k,"*")
Print x
Next
End Sub

A.
*
* *
* * *
B.
1 *
2 *
3 *
C.
3 *
2 * *
1 * * *
D.
* * *
* *
*