单项选择题

在窗体中有一个命令按钮Command1,编写事件代码如下:
  Private Sub Command1_Click()
  Dim s As Integer
  s = p(1) + p(2) + p(3) + p(4)
  debug.Print s
  End Sub
  Public Function p (N As Integer)
  Dim Sum As Integer
  Sum = 0
  For i = 1 To N
  Sum = Sum + 1
  Next i
  P = Sum
  End Function
  打开窗体运行后,单击命令按钮,输出的结果是()

A.15
B.20
C.25
D.35