如下程序的功能是删除文本框Text1中的数字字符。请在_________处填入适当的内容，完善程序。
Private Sub Command1_Click()
    Dim i%, s
    s = ""
    For i = 1 To Len(Text1.Text)
        c = Mid(Text1.Text, i, 1)
        If _________ Then
            s = s + c
        End If
    Next
    Text1.Text = s
End Sub
A、c >= "0" And c <= "9" 
B、c >= 0 And c <= 9 
C、c "9" 
D、c = 9