(a) The commissioner shall make regulations governing the training and certification of all persons requiring certification employed in the public schools of the State. The certificates issued pursuant to such regulations shall be of the following general classifications:

(b) The commissioner shall issue a regional credential pursuant to the provisions of section 80-5.8 of this Title.

(c) Any school district in the State may employ unusually qualified persons as visiting lecturers to supplement the regular program of instruction provided that said persons are licensed in accordance with the regulations of the Commissioner of Education.