单项选择题

以下是替换字符串中制定字符的函数过程:
Function sReplace (SearchLine As String,SearchFor As String,Replace With As
String) As String
Dim vSearchLine As String,found As Integer
found=InStr (SearchLine,SearchFor):vSearchLine=SearchLine
If found <>0 Then
vSearchLine=" "
If found>1 Then vSearchLine=Left (SearchLine,found -1)
      vSearchLine=vSearchLine+ReplaceWith
   End If
   If(表达式)<Len(SearchLine)Then
     vSearchLine=vSearchLine+Rights (SearchLine,Len (SearchLine)
                    ―found―Len(SearchFor)+1)
     End If
  End If
    sReplace=vSeachLine
  End Function
过程中的“表达式”应为( )。

A.found
B.found-1
C.found+Len(SearchFor)
D.found+Len(SearchFor)-1