单项选择题

单击命令按钮时,下列程序的执行结果是  Private Sub Commandl_Click( )    BT 4  End Sub  PriVate Sub BT(x As Integer)    X=X * 2 + 1    If x <6 Then     Call BT(x)    End If    X=x * 2    Print x;  End Sub

A.15
B.16
C.17
D.18