( d) The sale or supply by their nationals or from their territories of any commodities or products ( whether or not originating in their territories, but not including supplies intended strictly for medical purposes, educational equipment and material for use in schools and other educational institutions, publications, news material and, in special humanitarian circumstances, food-stuffs) to any person or body in Southern Rhodesia or to any other person or body for the purposes of any business carried on in or operated from Southern Rhodesia, and any activities by their nationals or in their territories which promote or are calculated to promote such sale or supply;