【答案解析】

Bank A
London
England
Dear Sirs:

Upon our claiming on B Bank, London through our London Office reimbursement of our negotiation under the above Credit, we were informed that payment was effected by them under reserve for the reason that the Credit expired on 31 ^st March.
We wish to point out that according to your cable amendment of 10 ^th February the shipment and validity dates of the Credit were extended up to 31 ^st May. We presume that it might possibly be due to the failure on your part to advise the reimbursing bank in time of the said amendment, or the advice having gone astray. You are now requested to immediately authorize the B Bank, London to release the reserve.
It is hoped that similar cases will not occur in the future.