The following types of training that lead to gainful employment may be approved:

(a) Nationally accredited vocational training;

(b) Training and non-accredited vocational courses provided by a tribe;

(c) Training programs not operated by the tribe but approved by the service provider;

(d) Apprenticeship training supervised by a State apprenticeship agency or council or by the Federal Apprenticeship Training Service that is provided by a corporation or association that has been training bona fide apprentices for at least one year or any other apprenticeship program approved by the service provider; or

(e) OJT offered by a public or private business.