ASP.NET Core – The name ‘JsonRequestBehavior’ does not exist in the current context

Returning Json-formatted data:

public class ClientController : Controller
{
    public JsonResult CountryLookup()
    {
         var countries = new List<SearchTypeAheadEntity>
         {
             new SearchTypeAheadEntity {ShortCode = "US", Name = "United States"},
             new SearchTypeAheadEntity {ShortCode = "CA", Name = "Canada"}
         };

         return Json(countries);
    }
}