Reading Comprehension (2) Kee & Co. , Ltd 34 Regent Street London, UK Dear Sirs, Due to the rise in the world price of paper, from 1 January of next year, prices for our products are due to increase by 10% across the board. Since you are a valued customer of long standing, we wish to give you the opportunity to deal with the price increases by ordering now at the current prices. In addition, we are willing to give you a discount of 5% on all orders of more than $20, 000. We are aware that you do not have sufficient warehousing (仓储) for large quantities of reserve stock. In this circumstance, we would be prepared to hold paper for you to be delivered at your convenience. There will be no charge for warehousing at this end. We believe that you will see the advantages of this arrangement, which will save you at least 15% on paper purchases in the coming year. We look forward to your early reply. Yours faithfully, Tony Smith Chief Seller According to the passage, why are the prices of seller's products going to rise?