Dan is the plaintiff in a negligence suit against the Colorado Railroad Co. based on a train accident. Colorado requests production under FRCP 34 of "all medical records pertaining to any treatment Dan has received, from any medical provider or other health care professional, which the plaintiff alleges was required as a result of inju ries suffered in the accident that is the subject of this action." Dan responds that he does not have these medical records, which are retained by the doctors or hospitals that have treated him. Is this response proper?