Image Captcha Solven

using System;
using OpenQA.Selenium.Chrome;
using ImageTypers;
using OpenQA.Selenium;
using System.Threading;
using System.Collections.Generic;
using System.Linq;

namespace Test_Selenium
{
    class Program
    {
        static void Main(string[] args)
        {
            // Chrome Optionen festlegen
            ChromeOptions option = new ChromeOptions();
            //option.AddArgument("--headless");
            option.AddArguments("ignore-certificate-errors");

            // Chrome Service festlegen
            ChromeDriverService service = ChromeDriverService.CreateDefaultService();
            service.HideCommandPromptWindow = true;

            ChromeDriver WebDriver = new ChromeDriver(service, option);

            try
            {
                WebDriver.Navigate().GoToUrl("https://2captcha.com/demo/normal");               // go to normal test page
                                                                                                // get access token from: http://www.imagetyperz.com
                string token = "XXXX";
                ImageTypersAPI i = new ImageTypersAPI(token);

                // balance
                string balance = i.account_balance();
                Console.WriteLine(string.Format("Balance: {0}", balance));

                // optional parameters dict
                Dictionary<string, string> image_params = new Dictionary<string, string>();
                image_params.Add("iscase", "true");         // case sensitive captcha
                //image_params.Add("isphrase", "true");       // text contains at least one space (phrase)
                //image_params.Add("ismath", "true");         // instructs worker that a math captcha has to be solved
                //image_params.Add("alphanumeric", "1");      // 1 - digits only, 2 - letters only
                image_params.Add("minlength", "2");         // captcha text length (minimum)
                image_params.Add("maxlength", "5");         // captcha text length (maximum)

                Console.WriteLine("Waiting for captcha to be solved...");
                string captcha_id = i.submit_image("https://2captcha.com/template/demo/images/normal.jpg", image_params);
                Dictionary<string, string> response = i.retrieve_response(captcha_id);
                ImageTypers.Utils.print_response(response);

                var array = response.ToArray();
                var first = array[1];

                Console.WriteLine(first);

                //WebDriver.FindElementByXPath("/html/body/div[1]/div[2]/div/div/div/div[1]/div/div/div/div/div/div[2]/div/form/input").SendKeys(response);
            }
            finally
            {
                Console.WriteLine("Fertig");
                Console.ReadLine();
                WebDriver.Quit();
            }

        }

    }
}

Balance: $15.2308
Waiting for captcha to be solved...
Response
--------------------------------
  "CaptchaId" - "15842269"
  "Response" - "w9h5k"
  "Cookie_OutPut" - ""
  "Proxy_reason" - ""
  "Recaptcha score" - "0.00"
  "Status" - "Solved"
--------------------------------
[Response, w9h5k]
Fertig

[...]
Dictionary<string, string> response = i.retrieve_response(captcha_id);
var antwort = response["Response"];
[...]

WebDriver.FindElement(By.CssSelector("form input"));
oder
WebDriver.FindElement(By.CssSelector("input[name='answer']"));