单选题 ______ is the budgeted amount for the work actually completed on the schedule activity or WBS component during a given time period.
A. Planned value B. Earned value
C. Actual cost D. Cost variance

【正确答案】 B
【答案解析】挣值是在给定时期内按进度活动或WBS部件所实际完成工作的预算值。