What is the purpose of a project charter ？（）

A．To address and document the characteristics and boundaries of the project and its associated products and service

B．To formally authorize the project and provide the project manager with the authority to apply organizational resource

C．To link the project，which is going to be planned，executed，and monitored/controlled to the ongoing work of the organizatio

D．To break down the scope of the project into smaller，better manageable components for further planning and estimatin

当尖轨与心轨因扭转或等原因造成（），且对行车平稳性有影响，应进行修理或者更换。

A.磨损

B.磨耗

C.光带异常

D.光带不良