No, none of those combinations are possible because the inputbox does not recognize Ctrl or Alt.
You could use Shift+a, Shift+b, ...
Code:
Sub ScratchMacro()
'A basic Word macro coded by Greg Maxey, http://gregmaxey.com/word_tips.html, 8/1/2017
Dim lngIndex As Long
Dim strMacro As String
lngIndex = 1
Do
Select Case lngIndex
Case 1: Macro_1
Case 2: Macro_2
Case 3: Macro_3
Case 4:
Macro_4
'This is the last macro
Exit Do
End Select
strMacro = InputBox("Macro " & lngIndex & " complete. Enter the next macro number or click ok", "Next Macro", "Ok")
Select Case strMacro
Case "Ok"
lngIndex = lngIndex + 1
Case Else
lngIndex = Asc(strMacro) - 64
End Select
Loop
lbl_Exit:
Exit Sub
End Sub
Sub Macro_1()
'Whatever
End Sub
Sub Macro_2()
'Whatever
End Sub
Sub Macro_3()
'Whatever
End Sub
Sub Macro_4()
'Whatever
End Sub