单项选择题

单击命令按钮时,下列程序的执行结果是
Private Sub Command1_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