单选题 The most crucial time for project risk assessment is______.
A. when a problem surfaces
B. during the planning phase
C. during the close-out phase
D. after the project schedule has been published

【正确答案】 B

【答案解析】[解析] 进行项目风险评估最关键的时候是：规划阶段(during the planning phase)。
选项A：问题出现时。选项C：结束阶段。选项D：项目进度公布之后。