自定义函数delStr(S，m)的功能是删除字符串S中第m位上的字符，

Function delStr(S As String, m As Integer) As String

Dim n As Integer

n = Len(S)

If m < 1 Or m > n Then

delStr = ”输入位置有误！”

ElseIf m = 1 Then

delStr = Mid(S, 2, n - 1)

ElseIf m < n Then

                

ElseIf m = n Then

delStr = Mid(S, 1, n - 1)

End If

End Function

则横线处代码填写正确的是(  )

A、delStr = Mid(S, 1, m) + Mid(S, m + 1, n)

B、delStr = Mid(S, 1, m - 1) + Mid(S, m , n)

C、delStr = Mid(S, 1, m) + Mid(S, m, n - m)

D、delStr = Mid(S, 1, m - 1) + Mid(S, m + 1, n - m)