(a) in the case of goods exported by rail, post, air or sea, the customs office competent for the place where the goods are taken over under a single transport contract for transport to a third country by the railway companies, the postal authorities, the airlines or the shipping companies; (b) in the case of goods exported by pipeline and of electrical energy, the office designated by the Member State where the exporter is established; (c) in the case of goods exported by other means or in circumstances not covered by (a) and (b), the last customs office before the goods leave the customs territory of the Community., office of exit - the customs office via which goods accompanied by an ATA carnet leave the customs territory of the Community