【单选题】

Quality assurance(QA) ______ .
A．is the application of planned, systematic quality activities to ensure effective policing of the conformance of the project team to approved specifications

B．is primarily concerned with providing the project team and stakeholders with standards, by which the project performance is measured
C．is the application of planned, systematic quality activities to ensure that the project will employ all processes needed to meet requirements
D．generally reduces the probability of project completion on schedule