Program.cs
 

using System;

namespace MyApplication
{
  class Program
  {
    static void MyMethod(string country = "Norway")
    {
      Console.WriteLine(country);
    }

    static void Main(string[] args)
    {
      MyMethod("Sweden");
      MyMethod("India");
      MyMethod();
      MyMethod("USA");
    }
  }
}

Result:
Sweden
India
Norway
USA