Section 3. Any municipality exercising the local option contained in section one shall, upon the recommendation of the chief executive officer or by a majority vote of the executive officers of a city or town, and after conducting a public hearing, adopt a personnel ordinance or by-law in accordance with the provisions of section four. Upon the majority vote of those voting on the referendum question, the application of chapter thirty-one, shall be rescinded with the following exceptions:
(a) all testing for municipal public safety positions shall be administered by the human resources division within the executive office for administration and finance in accordance with the provisions of chapter thirty-one;
(b) employees serving in positions subject to the provisions of chapter thirty-one on the effective date of this act, and their successors, may appeal disciplinary actions, decisions that the examination fairly tested the knowledge, skills and abilities required to perform the primary or dominant duties of the position for which the examination was held and the results of performance evaluations to the civil service commission pursuant to section eight. The said commission shall hear such appeals in accordance with the provisions of said chapter thirty-one; and
(c) the provisions of chapter thirty-one contained in sections twenty-five, twenty-six and twenty-eight providing for veterans' preference.