The eligible taxable income of a year of income of a person who is a prescribed person in relation to the year of income is the amount (if any) remaining after deducting from the eligible assessable income of the person of the year of income:
(a) any deductions allowable to the person in relation to the year of income that relate exclusively to that eligible assessable income;
(b) so much of any other deductions (other than apportionable deductions) allowable to the person in relation to the year of income as, in the opinion of the Commissioner, may appropriately be related to that eligible assessable income; and
(c) the amount that bears to the apportionable deductions allowable to the person in relation to the year of income the same proportion as the amount that, but for this paragraph, would be the eligible taxable income of the person of the year of income bears to the sum of:
(i) the taxable income of the person of the year of income; and
(ii) the apportionable deductions allowable to the person in relation to the year of income.