(a) in the case referred to in clause (i) of this sub- section has, prior to the issue of notice to him under sub- section (2) of section 14, voluntarily and in good faith, made full disclosure of his net wealth; and in the case referred to in clause (ii) of this sub- section has, prior to the detection by the Wealth- tax Officer of the concealment of particulars of assets or of the inaccuracy of particulars furnished in respect of the assets or debts in respect of which the penalty is imposable, voluntarily and in good faith, made full and true disclosure of such particulars;

(b) has co- operated in any enquiry relating to the assessment of the wealth represented by such assets; and

(c) has either paid or made satisfactory arrangements for payment of any tax or interest payable in consequence of an order passed under this Act in respect of the relevant assessment year: 1[ Provided that if in a case falling under clause (c) of sub- section (1) the amount in respect of which penalty is imposable for the relevant assessment year, or where such disclosure relates to more than one assessment year, such amount for any one of the relevant assessment years, exceeds five hundred thousand rupees, no order reducing or waiving the penalty shall be made by the Commissioner unless the previous approval of the Board has been obtained.]