(a) In selecting a candidate for promotion, it is not, itself, a violation of this article, for an employer to limit the group of eligible candidates to members of the employer's existing workforce or to give a preference in selection to an incumbent employee over a candidate who is not an incumbent employee. However, in evaluating or selecting candidates for promotion from among its existing workforce, it is discrimination on the basis of age for an employer to evaluate unequally or to fail to select a candidate who is over 40 because of the age of the candidate.

(b) In selecting a candidate for promotion, it is not, itself, a violation of this article for an employer to promote a candidate under the age of 40 in preference to a candidate over 40 on the basis of the superior experience and training of the younger candidate, or on the basis of other legitimate reasons, so long as age is not a factor.

(c) It is discrimination on the basis of age for an employer to deny an employee the opportunity to gain the experience and training necessary to achieve promotion, because such employee is over 40.