(a) Persons authorized under the laws of this state to practice medicine and surgery or osteopathy;
(b) Persons, firms and corporations who sell eyeglasses or spectacles in a store, shop or other permanently established place of business on prescriptions from persons authorized under the laws of this state to practice either optometry or medicine and surgery;
(c) Persons, firms and corporations who manufacture or deal in eyeglasses or spectacles in a store, shop or other permanently established place of business, and who neither practice nor attempt to practice optometry.