YES OCP

Program.cs

class Program
{
    static void Main(string[] args)
    {
        PhoneFactory pf1 = new PhoneFactory();
        pf1.MakePhone(new Iphone());
        
        PhoneFactory pf2 = new PhoneFactory();
        pf2.MakePhone(new Samsung());
        
        PhoneFactory pf3 = new PhoneFactory();
        pf3.MakePhone(new Xiaomi());
        
        Console.ReadLine();
    }
}