This way of instanciating a class is totally valid in C# 3.0

valid.cs

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

namespace ConsoleApplication3
{
    class Program
    {
        public class Person{
            private string _firstName;
            private string _lastname;

            public Person() {}

            public string Firstname {
                get{
                    return _firstName;
                }
                set
                {
                    _firstName = value;
                }
            }

            public string Lastname
            {
                get
                {
                    return _lastname;
                }
                set
                {
                    _lastname = value;
                }
            }


            }
        static void Main(string[] args)
        {
            Person p1 = new Person
            {
                Firstname = "Jyoti",
                Lastname = "Tuladhar"
            };
            Console.WriteLine(p1.Firstname.ToString());

            Console.ReadLine();
        }
    }
}