(1) If the LEA has not sent a prior written notice under §300.503 to the parent regarding the subject matter contained in the parent’s due process complaint, the LEA must, within 10 days of receiving the due process complaint, send to the parent a response that includes—
(i) An explanation of why the agency proposed or refused to take the action raised in the due process complaint;
(ii) A description of other options that the IEP Team considered and the reasons why those options were rejected;
(iii) A description of each evaluation procedure, assessment, record, or report the agency used as the basis for the proposed or refused action; and
(iv) A description of the other factors that are relevant to the agency’s proposed or refused action.