Program

using System;
using System.IO;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main()
        {
            //Search in current directory only.
            String[] dirs1 = Directory.GetDirectories("D:/Sample", "Green color",SearchOption.TopDirectoryOnly);

            if (dirs1.Length == 0)
            {
                Console.WriteLine("1.Directory Not Found");
            }
            else
            {
                Console.WriteLine("Sub directories are:");
                for (int i = 0; i < dirs1.Length; i++)
                {
                    Console.WriteLine("\t" + dirs1[i]);
                }
            }

            //Search into all current directory .
            String[] dirs2 = Directory.GetDirectories("D:/Sample", "Green color", SearchOption.AllDirectories);

            if (dirs2.Length == 0)
            {
                Console.WriteLine("2.Directory Not Found");
            }
            else
            {
                Console.WriteLine("Sub directories are:");
                for (int i = 0; i < dirs2.Length; i++)
                {
                    Console.WriteLine("\t" + dirs2[i]);
                }
            }
        }
    }
}

Output

1.Directory Not Found
Sub directories are:
        D:/Sample\dir1\Green color
        D:/Sample\dir2\Green color

Note: In above program, we need to remember, when we use "Directory" class, System.IO namespace must be included in the program.