听力原文:If a letter of credit is issued irrevocably, it can't be canceled nor amended without permission. (4) A.An irrevocable L/C can not be committed to amendment. B.An irrevocable L/C can not be cancelled without permission. C.An irrevocable L/C can not be cancelled or amendeD. D.Neither cancellation nor amendment without permission can be made to the irrevocable L/C.