Ari is a metal broker who was in negotiations with three parties for the sale of a large consignment of copper he was expecting to receive on 15 March.On 1 March he wrote to the three clients Bas, Cas and Das.He wrote to Bas offering to supply the copper at $6,000 per tonne for orders over 100 tonnes for delivery to be made before 1 May. Bas immediately wrote back ordering 75 tonnes for delivery on 30 April.He wrote to Cas offering 100 tonnes of copper at $6,500 per tonne if he placed an order before 1 May. Cas also immediately wrote back ordering 150 tonnes at the agreed price for delivery on 30 April.He wrote to Das offering to supply him copper at $6,750 per tonne and Das immediately wrote back ordering 150 tonnes for delivery on 1 May.After he had sent the above letters and before he received the replies Ari discovered that he would not be able to secure the delivery of the copper.Required:Advise Ari as to his potential liability to Bas, Cas and Das under the above situations, assuming that the United Nations Convention on Contracts for the International Sale of Goods applies. (10 marks)

使用绩效报告可以？（）

A、进行风险分析

B、只适用于大型项目

C、使人察觉项目问题所在

D、规定项目成员的纪律