<p>using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.IO;
using System.Xml;
using System.Text.RegularExpressions;

public interface IStringUtilities
{
  string ConvertPlainTextUrlsToHtmlHyperlinks(string input, HyperlinkOptions options = HyperlinkOptions.None);
}

public class Solution : IStringUtilities
{
  public string ConvertPlainTextUrlsToHtmlHyperlinks(string input, HyperlinkOptions options = HyperlinkOptions.None)
  {
    var regex = 
      @"((www\.|(http|https|ftp|news|file)+\:\/\/)[_.a-z0-9-]+\.[a-z0-9\/_:@=.+?,##%&amp;~-]*[^.|\'|\# |!|\(|?|,| |&gt;|$1",target, noFollow));
  }
}
public enum HyperlinkOptions
{
	None = 0,
	OpenInNewWindow = 1,
	NoFollow = 2
}</p>