单项选择题

在窗体上画一个命令按钮,名称为Command1。然后编写如下程序:
Private Sub Command1_ Click()
Dim a As Integer, b As Integer
b = 1
for a = 1 To 100
if b>= 10 then exit for
if b Mod 3 = 1 then
b=b+3
End if
Next a
Print a
End Sub
在命令按钮上单击后,窗体上显示的结果是______。

A.101
B.6
C.5
D.4