Provided that nothing in this sub-clause shall authorise the detention of any person beyond the maximum period prescribed by any law made by Parliament under sub-clause (b) of clause (7); or (b) such person is detained in accordance with the provisions of any law made by Parliament under sub-clauses (a) and (b) of clause (7). (5) When any person is detained in pursuance of an order made under any law providing for preventive detention, the authority making the order shall, as soon as may be, communicate to such person the grounds on which the order has been made and shall afford him the earliest opportunity of making a representation against the order. (6) Nothing in clause (5) shall require the authority making any such order as is referred to in that clause to disclose facts which such authority considers to be against the public interest to disclose. (7) Parliament may by law prescribe—  (a) the circumstances under which, and the class or classes of cases in which, a person may be detained for a period longer than three months under any law providing for preventive detention without obtaining the opinion of an Advisory Board in accordance with the provisions of subclause (a) of clause (4);  (b) the maximum period for which any person may in any class or classes of cases be detained under any law providing for preventive detention; and  (c) the procedure to be followed by an Advisory Board in an inquiry under sub-clause (a) of clause (4).  Sub-clause (a) shall stand omitted by the Constitution (Forty-fourth Amendment) Act, 1978, s. 3(b)(i) (date to be notified).  Sub-clause (b) shall stand re-lettered as sub-clause (a) by s. 3(b)(ii), ibid. (date to be notified).  Sub-clause (c) shall stand re-lettered as sub-clause (b) by s. 3(b)(iii), ibid. (date to be notified).  Sub-clause (a) of clause (4) shall stand substituted as "clause (4)" by s. 3(b)(iii), ibid. (date to be notified). 44