发送的电子邮件仍然包含HTML标签

我正在给使用模板的人发送电子邮件。问题是所有的标签都显示出来了。

<p>Hello,</p>
<p> Please, click the following link to change your password </p>
//...
<p> PLEASE DO NOT REPLY TO THIS MESSAGE</p>

收到的邮件精确地显示带有所有标签的原始消息。有没有办法让它看起来像

下面是我的代码:

string path = System.Web.HttpContext.Current.Server.MapPath("~/path/myTemplate.txt");
String body;
using (StreamReader sr = new StreamReader(path))
{
   body = sr.ReadToEnd();
}
body = body.Replace("<%PasswordLink%>", pwdLink);
var mail = new MailMessage("from", "to");
mail.Subject = "Password Reset";
mail.Priority = MailPriority.High;
mail.Body = body;
var client = new SmtpClient();
client.Port = 25;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.Host = "123.45.67.89";
client.Send(mail);