using System;

public class Client

{

    public String Name { get; set;}

    public BankAccount Account {get; set;}

    public class BankAccount

    {

        public Decimal Balance {get; set;} = 99.9m;

    }

    class Program

    {

        static void Main(string[] args)

        {

            Client dillan = new Client() {Name = "Dillan"};

            Nullable<Decimal> dillanBalance = dillan?.Account?.Balance;

            Console.WriteLine($"New client created: {dillan?.Name} with balance {dillanBalance}");

        }

    }

}