.net Web API 2,return HttpResponseMessage with ObjectContent

public async TaskHttpResponseMessage Register(AllenRegistration model) { 1. Will return 400 Error return Request.CreateResponse( HttpStatusCode.BadReques t); 2. Will return Json Type like {return1:A,returnBL:B} return new HttpResponseMessa

public async Task Register(AllenRegistration model)

{

1.

Will return 400 Error 

  return Request.CreateResponse(HttpStatusCode.BadRequest);

2.

Will return Json Type like   {"return1":"A","returnB"L:"B"}

return new HttpResponseMessage(HttpStatusCode.OK)

            {
                Content = new ObjectContent