Which definition below best describes cost aggregation?

A. A risk management technique to view costs and their risks by an aggregated group instead of by an individual work package.

B. Adding the costs associated with each work package back up to the parent nodes on the WBS to ultimately get a total project cost.

C. Multiplying the costs with each work package by a multiplier to calculate the needed reserve.

D. Aggregating the costs associated with work packages back to a single point in time to eliminate the time value of money.