A company convenes an estimating team to bid competitively on a project．Later, a negotiation team made up of different people is established to negotiate the final price．The project manager was not part of either team and is assigned after negotiations were completed and the contract was signed．A good project manager should mainly:（　）
A．Disregard the assumptions/constraints used in estimating the job
B．Review the documents that authorize the project and define its objectives
C．Focus heavily on comparing the contractual statement of work with the proposal statement of work
D．Request a new project charter