<prompt> Translate the following text to SwahiliHowever, if there are categories of mail that are attractive to competitors, these categories should be viewed as extremely elastic and the Postal Service would be expected to move its rates toward a lower markup over costs.  <response>: Hata hivyo, kama kuna makundi ya barua ambayo ni kuvutia kwa washindani, makundi haya lazima kuonekana kama elastic sana na huduma ya posta inatarajiwa kuhamia viwango vyake kuelekea chini markup juu ya gharama. 