(a) Applications. This section applies to each educational institution to which subpart C applies which:
(1) Admitted only students of one sex as regular students as of June 23, 1972; or
(2) Admitted only students of one sex as regular students as of June 23, 1965, but thereafter admitted as regular students, students of the sex not admitted prior to June 23, 1965.
(b) Provision for transition plans. An educational institution to which this section applies shall not discriminate on the basis of sex in admission or recruitment in violation of subpart C unless it is carrying out a transition plan approved by the United States Commissioner of Education as described in Sec. 15a.18, which plan provides for the elimination of such discrimination by the earliest practicable date but in no event later than June 23, 1979.