I am trying to retrieve Value's using Key's in the JSON returned. 
I tried the following but, none worked.
1.)
string email= json.emailAddress;
2.)
string email= json["emailAddress"].ToString();
Complete Code
 var api= new Uri("https://api.linkedin.com/v1/people/~:(picture-url)?format=json");
 using (var webClient = new WebClient())
 {
       webClient.Headers.Add(HttpRequestHeader.Authorization, "Bearer " + token);
       webClient.Headers.Add("x-li-format", "json");
       dynamic  json = webClient.DownloadString(api);
  }
JSON returned
{
  "emailAddress": "[email protected]",
  "firstName": "xxx",
  "formattedName": "xxxx xxxx",
  "id": "xxxxxx",
  "lastName": "xxxxxx",
}
    
dynamicis good to use, but when you know the return type of a method you should declare the variable of that type, i.e.string json = webClient.DownloadString(api);. Usingdynamicdoesn't give your variable magical properties - if it's astringit's still astringwithdynamic.