Something like this:

    HtmlDocument doc = new HtmlDocument();
    doc.Load(yourHtmlFile);

    foreach (HtmlNode node in doc.DocumentNode.SelectNodes("//text()[normalize-space(.) != '']"))
    {
        Console.WriteLine(node.InnerText.Trim());
    }

Will output this:

Select your Age:
0 to 10
20 and above
Help/Hints:
This is required field.
Make sure select the right age.
Learn More