using System;

using System.Collections.Generic;

using System.Linq;

public class Account {

    public string Name { get; set; }

    public string Email {get; set; }

}

public class Program

{

    private static List<Account> Accounts = new List<Account> { new Account { Name = "John", Email = "john@john.com" } };

    //private static List<Account> Accounts = new List<Account> { new Account { Name = "John", Email = null } };

    //private static List<Account> Accounts = new List<Account> { new Account { Name = "Joe", Email = null } };

    //private static List<Account> Accounts = null;

​

    public static void Main() {

        string Email = Accounts?.Where(x => x.Name == "John").Select(z => z.Email).First() ?? string.Empty;

        Console.WriteLine(Email == null);

        Console.WriteLine(Email);

    }

}