Introduction

I have used Visual Studio 2012 for debugging purpose. But you can use any version of visul studio as per your availability.

using System;
using System.Linq;
using System.Collections.Generic;
 
class LinqExercise
{
    static void Main(string[] args)
    {
        var itemlist = (from c in Item_Mast.Getitem()
                        select c.ItemDes)
                   .Distinct()
                   .OrderBy(x => x);
 
        foreach (var item in itemlist)
            Console.WriteLine(item);
        Console.ReadLine();
    }
}
class Item_Mast
{
    public int ItemId { get; set; }
    public string ItemDes { get; set; }
 
    public static List<Item_Mast> Getitem()
    {
        List<Item_Mast> list = new List<Item_Mast>();
        list.Add(new Item_Mast() { ItemId = 1, ItemDes = "AUDI" });
        list.Add(new Item_Mast() { ItemId = 2, ItemDes = "BMW" });
        list.Add(new Item_Mast() { ItemId = 3, ItemDes = "BUGATTI" });
        list.Add(new Item_Mast() { ItemId = 4, ItemDes = "HONDA" });
        list.Add(new Item_Mast() { ItemId = 6, ItemDes = "FERRARI" });
        list.Add(new Item_Mast() { ItemId = 6, ItemDes = "AUDI" });
        list.Add(new Item_Mast() { ItemId = 5, ItemDes = "JAGUAR" });
        list.Add(new Item_Mast() { ItemId = 6, ItemDes = "FERRARI" });
        return list;
    }
}

Result