Declaring and using multidimensional array in C#

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

namespace ForgetCode
{   
    public class MainClass
    {
        public static void Main()
        {

            // Multidimensional arrays.
            int[,] numbers = new int[3, 2] { { 1, 2 }, { 3, 4 }, { 5, 6 } };
            string[,] siblings = new string[2, 2] { { "Mike", "Amy" }, { "Mary", "Albert" } };

            //Omitting size
            int[,] numbers2 = new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 } };
            string[,] siblings2 = new string[,] { { "Mike", "Amy" }, { "Mary", "Albert" } };

            //Without New operator
            int[,] numbers3 = { { 1, 2 }, { 3, 4 }, { 5, 6 } };
            string[,] siblings3 = { { "Mike", "Amy" }, { "Mary", "Albert" } };
        }
    }
}