 Reasons that are not valid for termination of contracts include (a) union membership or participation in union activities outside working hours or, with the consent of the employer, within working hours; (b) seeking office as, acting or having acted in the capacity of, an employee's representatives; (c) the filing of a complaint, the participation in proceedings against an employer involving alleged violation of laws or recourse to administrative authorities; (d) race, colour, sex, marital status, family responsibilities, pregnancy, religion, political opinion or affiliation, ethnicity, tribal affiliation or social status of the employee; or (e)absence from work during leave or a rest period in accordance with a written law. 