Request.CreateResponse Error

Question

I am getting an error below in red, I am not for sure why. I am using Project MVC4 project  (API Controller):

Error I am getting:

ErrorThe type arguments for method 'System.Net.Http.HttpRequestMessageExtensions.CreateResponse<T>(System.Net.Http.HttpRequestMessage, System.Net.HttpStatusCode, T)' cannot be inferred from the usage. Try specifying the type arguments explicitly.

   var ret = new

                {

                    CommentedBy = postcomment.CommentedBy,

                    CommentedByName = usr.Fullname,

                    //CommentedByAvatar = imgFolder + (String.IsNullOrEmpty(usr.AvatarExt) ? defaultAvatar : postcomment.CommentedBy + "." + postcomment.UserProfile.AvatarExt),

                    CommentedByAvatar = imgFolder + (String.IsNullOrEmpty(usr.AvatarExt) ? defaultAvatar : postcomment.CommentedBy + "." + postcomment.UserProfile.AvatarExt),

                  

                    CommentedDate = postcomment.CommentedDate,

                    CommentId = postcomment.CommentId,

                    Message = postcomment.Message,

                    PostId = postcomment.PostId

                };

                HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, ret);