删除字符串中的非字母字符，并查找出ASCII码值最大的字母。程序功能如下: 在文本框Text1中输入一个字符串，单击命令按钮Command1，在文本框Text2中显示删除非字母字符后的字符串，在文本框Text3中显示ASCII码值最大的字母，运行界面如图所示。
（1）程序中的Command1_Click()属于____________。（单选，填代码:
| A．对象名/ | B．事件名/ | C．属性名/ | D．事件处理过程名） |
（2）实现上述功能的VB程序如下，请在划线处填入合适代码。
Private Sub Command1_Click()
Dim result As String, s As String, c As String, cmax as string
Dim i As Integer, j As Integer
s = Text1.Text
Text2.Text = ""
For i = 1 To Len(s)
①_________
If c >= "A" And c <= "Z" Or c >= "a" And c <= "z" Then
result =
②______
End If
Next i
Text2.Text = result
j = 2
cmax = Mid(result, 1, 1)
Do While j <= Len(result)
If Mid(result, j, 1) > cmax Then cmax = Mid(result, j, 1)
③________
Loop
Text3.Text = cmax
End Sub
