using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var regex = new Regex(@"(?<mode>[A-Z]+)([ \-:]+(?<responses>[A-Z; ]+\b))?");

        var values = new[] {

            "<!-- MOCK -->",

            "<!--MOCK-->",

            "<!-- MOCK:SENT;FAIL -->",

            "<!--MOCK:SENT;SUCCESS-->",

            "<!--MOCK:SENT; SUCCESS-->",

            "<!--MOCK:SENT ; SUCCESS-->",

            "<!--MOCK:SENT -->",

            "<!-- MOCK:SENT-->",

            "<!-- MOCK : SENT -->",

            "<!-- MOCK: SENT -->",

            "<!-- MOCK :SENT -->",

        };

        foreach (var value in values)

        {

            var match = regex.Match(value);

            Console.WriteLine($"Mode: [{match.Groups["mode"].Value}], Responses: [{match.Groups["responses"].Value}]");

        }

    }

}