Product, Category, Composition and Inheritance, C#

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//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

// aljodav
// http://rextester.com/users/376

namespace ForInstance
{
    public interface ICategory{string Name{get;}string Account{get;}}
    public abstract class Category:ICategory{public string Name{get;protected set;}public string Account{get;protected set;}}
    
    public class Hardware:Category{
        public Hardware(){Name="Hardware";Account="07-HD-603N";}
    }
    // class AnotherCategory:Category{...}
    
    public interface IProduct{string Name{get;}int Id{get;}ICategory Category{get;}}
    public class Product:IProduct,IComparable<Product>{
        public int CompareTo(Product p){return this.Name.CompareTo(p.Name);}
        
        public string Name{get;set;}
        public int Id{get;set;}
    
        public ICategory Category{get;set;}
    }
}

namespace Rextester
{
    using Category=ForInstance.Category;
    using Hardware=ForInstance.Hardware;
    using Product=ForInstance.Product;
    public class Program
    {
        public static void Main(string[] args)
        {
            // the unique Category object; this object has NO item to be defined in the public Main method.
            Category hardware= new Hardware();
            
            Product mobo= new Product{Name="Mother Board",Id=101,Category=hardware};
            Product fan= new Product{Name="Fan",Id=3,Category=hardware};
            
            Product[] ps={
                mobo,
                new Product{Name="Digital to Analog Converter",Id=531,Category=hardware},
                new Product{Name="CPU",Id=332211,Category=hardware},
                new Product{Name="Memory",Id=55,Category=hardware},
                fan,
            };
            
            Array.Sort(ps);
            Array.ForEach(ps,p=>Console.WriteLine("• {0,-28}• {1,-10}• {2,-15}• {3}",p.Name,p.Id,p.Category.Name,p.Category.Account));
        }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,12 sec, absolute running time: 0,09 sec, cpu time: 0,09 sec, average memory usage: 13 Mb, average nr of threads: 3