Sort string file

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
//Write a program that reads a text file containing a list of strings, sorts them and saves them to another text file
class Sort
{
    static void Main()
        {
            using(StreamReader reader = new StreamReader("unsorted.txt"))
            using (StreamWriter writer = new StreamWriter("sorted.txt"))
            {
                List<string> unsorted = new List<string>();
                ReadFile(reader, unsorted);
                List<string> sorted = new List<string>();
                SortList(unsorted, sorted);
                WriteFile(writer, sorted);
            }
        }

    private static void WriteFile(StreamWriter writer, List<string> sorted)
    {
        for (int i = 0; i < sorted.Count; i++)
        {
            writer.WriteLine(sorted[i]);
        }
    }

    private static void SortList(List<string> unsorted, List<string> sorted)
    {
        var sort = from s in unsorted
                   orderby s
                   select s;
        foreach (var item in sort)
        {
            sorted.Add(item);
        }
    }

    private static void ReadFile(StreamReader reader, List<string> unsorted)
    {
        string line;
        while ((line = reader.ReadLine())!=null)
        {
            unsorted.Add(line);
        }
    }
}