Почему строка кода подчёркнута красной линией? - C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using OpenQA.Selenium;
//****//
using System.Diagnostics;
using OpenQA.Selenium.Chrome;
using System.IO;
//****//
 
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        IWebDriver Browser;
 
        public Form1()
        {
            InitializeComponent();
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            OpenQA.Selenium.Chrome.ChromeOptions co = new OpenQA.Selenium.Chrome.ChromeOptions();
            co.BinaryLocation = @"c:\soft\UD\GoogleChromePortable\1_1\GoogleChromePortable_1.exe";
            co.AddExtensions(new File(@"c:\soft\UD\GoogleChromePortable\1_1\Data\profile\SiteGeoIPLocator.crx"));
            co.AddArguments(@"c:\soft\UD\GoogleChromePortable\1_1\Data\profile\SiteGeoIPLocator.crx");
 
            // co.AddExtension(Path.GetFullPath("c:\soft\UD\GoogleChromePortable\1_1\profil\SiteGeoIPLocator\SiteGeoIPLocator.crx"));
 
            // chrome://extensions/
            //****//
            Browser = new OpenQA.Selenium.Chrome.ChromeDriver(co);
            Browser.Manage().Window.Maximize();
            Browser.Navigate().GoToUrl("http://google.com");
 
            IWebElement SearchInput = Browser.FindElement(By.Id("lst-ib"));
            SearchInput.SendKeys("проект домов" + OpenQA.Selenium.Keys.Enter);
 
        }
 
        private void button2_Click(object sender, EventArgs e)
        {
 
        }
    }
}