Matter is exempt matter if its disclosure could reasonably be expected to—
(a) prejudice the effectiveness of a method or procedure for the conduct of tests, examinations or audits by an agency; or
(b) prejudice the attainment of the objects of a test, examination or audit conducted by an agency; or
(c) have a substantial adverse effect on the management or assessment by an agency of the agency's personnel; or
(d) have a substantial adverse effect on the conduct of industrial relations by an agency;
unless its disclosure would, on balance, be in the public interest.