using System.Collections.Generic;

using System;

​

​

public class Program

{

    public static void Main()

    {

        string ad = "class= adsbygoogle style= display:block;text-align:center; data-ad-layout= in-article data-ad-format= fluid data-ad-client= ca-pub-5105528667051233 data-ad-slot= 1029303696";

        string stringWithQoutes = AddQoutesToAd(ad);

        Console.WriteLine(stringWithQoutes);

    }

    private static string AddQoutesToAd(string input){

         input = input.Replace(" ","\" ");

        input = input.Insert(input.Length,"\"");    

        return input;

    }

}