using System;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var asd = new int[3][];

        asd[0] = new[]{3, 4, 5};

        asd[1] = new[]{1, 2, 3};

        asd[2] = new[]{0, 1, 2};

        var afterSort = asd.OrderBy(x => x[0]);

        foreach (var item in afterSort)

            Console.WriteLine(string.Join(", ", item));

    }

}