Resposta - Registro de Clientes

Classe Person:

namespace exercise84.Models;

internal class Person
{
    public string Name { get; }
    public int Age { get; }

    public Person(string name, int age)
    {
        Name = name;
        Age = age;
    }
}

Classe VipCustomer:

namespace exercise84.Models;

internal class VipCustomer : Person
{
    public string Level { get; }
    public string VipCode { get; }

    public VipCustomer(string name, int age, string level, string vipCode)
        : base(name, age)
    {
        Level = level;
        VipCode = vipCode;
    }

    public override string ToString()
    {
        return $"Welcome, VIP customer: {Name}\nAge: {Age}\nLevel: {Level}\nVIP Code: {VipCode}\n";
    }
}

Instâncias:

using exercise84.Models;

VipCustomer cliente1 = new VipCustomer("Renata", 32, "Gold", "VIP123A");
VipCustomer cliente2 = new VipCustomer("Leonardo", 40, "Diamond", "VIP789X");

Console.WriteLine(cliente1);
Console.WriteLine(cliente2);