<prompt> Translate the following text to SwahiliThe delivery function is the most important source of inherent cost differences between the geographic areas served by a post and, indeed between posts themselves.  <response>: Utoaji kazi ni chanzo muhimu zaidi ya tofauti za gharama asili kati ya maeneo ya kijiografia kuhudumiwa na post na, kwa kweli kati ya posts wenyewe. 