“pension fund”, in relation to any person, means –

(a)     a fund which has in respect of the year of assessment in question or any previous year of assessment been approved by the Commissioner as a pension fund under paragraph (c) of the definition of “pension fund” in section 1 or a corresponding definition in any previous Income Tax Act; or

(b)     a public sector fund (other than a fund referred to in paragraph (b) of the definition of “provident fund”), the rules of which wholly or mainly provide for annuities on retirement to its members,

if during any such year the person was a member of such fund;