During project exe cuting, a large number of changes are made to the project. The project manager should: A. wait until all changes are known and print out a new schedule. B. make approved changes as needed, but retain the schedule baseline. C. make only the changes approved by management. D. talk to management before any changes are made. 在项目执行阶段,项目发生了很多变更,项目经理应该: A.一直等待,直到了解了所有的变更,然后打印一个新的进度表。 B.根据需要尽快实施被批准的变更,但是保留原有的进度基准。 C.只实施管理层批准的变更。 D.实施任何变更前要通知管理层。