(iv) For purposes of computing time for responses to notices of intent to cancel accreditation, days means calendar days. In computing the time for filing this response, the date on which the notice was mailed by the Chief Counsel shall be excluded. A response postmarked prior to the expiration of the 30th day shall be accepted as timely filed. If the 30th day falls on a weekend or legal holiday, the first business day thereafter shall be included in the computation. As used in this section, legal holiday means New Year's Day, Birthday of Martin Luther King, Jr., Washington's Birthday, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day, Christmas Day, and any other day appointed as a holiday by the President or the Congress of the United States, or by the State in which the individual resides.