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