在窗体中有一个命令按钮Commandl,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+i Next i P=Sum End Function 打开窗体运行后,单击命令按钮,输出结果是 A. 15 B. 20 C. 25 D. 35