Imports System

'Note use of OR in this case                

Public Module Module1

    Public Sub Main()

        Dim UserChoise As Char

        Console.WriteLine("A - OptionA")

        Console.WriteLine("B - OptionB")

        Console.WriteLine("C - OptionC")

        Do

            Console.WriteLine("Enter choise (A/B/C)")

            UserChoise= Console.ReadLine()

        Loop Until UserChoise = "A" OR UserChoise = "B" OR UserChoise = "C"

    End Sub

End Module