Hello, I'm using gecko web browser, I couldn't find a way to select the radio button on the site and choose from the form field.

selecting radio button on site and selecting object from form on site

var links = geckoWebBrowser1.Document.GetElementsByTagName("input");
foreach (Gecko.DOM.GeckoInputElement link in links)
{
    if (link.GetAttribute("Name") == "title")
    {
        link.Value = "Best Bundle Layered 90 Files, Game SVG - UnderTale SVG - Under Svg - Tale Svg for Cricut - Digital File Active";
    }
   else if (link.GetAttribute("Name") == "quantity-input")
    {
        link.Value = "999";
    }
    var button = new GeckoButtonElement(geckoWebBrowser1.Document.GetElementById("listing-edit-image-upload").DomObject);
    button.Click();

    //var a = geckoWebBrowser1.Document.GetElementsByName("is_digital")[2].InvokeMember("click");// InvokeMember error
   // object p = geckoWebBrowser1.Document.GetElementsByTagName("input").GetElementsByName("is_digital")[2].InvokeMember("click");//GetElementsByName error

}

geckoWebBrowser1.Document.GetElementsByName("is_digital")[2].InvokeMember("click");// InvokeMember error
               // object p = geckoWebBrowser1.Document.GetElementsByTagName("input").GetElementsByName("is_digital")[2].InvokeMember("click");//GetElementsByName error