A letter of credit is a written promise of the（ ）actingat the request and on the instructions of the applicant or on its own behalf， is to make a payment to or to the order of the beneficiary， or is to accept and pay bill （s） of exchange drawn by the beneficiary，against stipulated document （s），provided that the terms and conditions of the L/C are complied with.

A.importer

B.exporter

C.issuing bank

D.buyer