4.—In this Part “business” includes any trade, profession or other occupation carried on, for reward or otherwise, either within or outside the State and includes also the performance of functions by or on behalf of—

(a) any person or body remunerated or financed wholly or partly out of moneys provided by the Oireachtas,

(b) any institution of the European Communities,

(c) any national or local authority in a jurisdiction outside the State, or

(d) any international organisation.