asp.net mvc file contenttype

  public ActionResult MyFile(string MetaValue,int OrganizationId=0)
    {          
            OrganizationUsersDataContext OrgMeta = new OrganizationUsersDataContext();
            JobsRepository JobsRespository = new JobsRepository();
            string CvPath = JobsRespository.GetCvPath();
            var FilePathForOrganization = OrgMeta.OrganizationMetas.FirstOrDefault(m => m.bit_IsDeletable == true && m.int_OrganizationId == OrganizationId && m.vcr_MetaKey == "PhysicalPath");
            string CompletePhysicalPath = FilePathForOrganization.vcr_MetaValue + CvPath +  MetaValue ;
            return File(@CompletePhysicalPath,"");

    }

My File can return doc,docx or pdf , what to have in content type . which is giving problem.