using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine($"Expected: True , Actual: {MustBeCharacter("stackoverflow?1234")}");   //Added question mark

        Console.WriteLine($"Expected: False , Actual: {MustBeCharacter("stackoverflow1234")}");   //Missing special character i.e. ?

    }

    private static bool MustBeCharacter(string arg)

    { 

        var specialChars = ".,?!*-+".ToCharArray();

        return specialChars.Any(x => arg.Contains(x));

    }   

}