“normal retirement age” means-

(a)     in the case of a member of a pension fund or provident fund, the date on which the member becomes entitled to retire from employment for reasons other than sickness, accident, injury or incapacity through infirmity of mind or body;

(b)     in the case of a member of a retirement annuity fund, a pension preservation fund or a provident preservation fund, the date on which the member attains 55 years of age; or

(c)     in the case of a member of any fund contemplated in this definition, the date on which that member becomes permanently incapable of carrying on his or her occupation due to sickness, accident, injury or incapacity through infirmity of mind or body;