A company wants to sign a 15-year contract with a supplier. Which type of contract should the project manager recommend? 一家公司希望与供应商签订为期15年的合同，项目经理应建议哪种合同类型？ ◑A.Firm fixed price固定总价合同 ◑B.Fixed price incentive fee总价加激励费用合同 ◑C.Time and Material contracts工料合同 ◑D.Fixed Price with Economic Price Adjustments总价加经济价格调整合同
