|A) None - Cost estimating requires details to be accurate||B) Use the cost of similar projects|
|C) Use a rule-of-thumb or per-square-foot estimate||D) Add up the costs on the WBS|
Although it is less accurate than adding up individual costs from the WBS, it is less time consuming. The trade-off is accuracy. Answer A is incorrect because to do a more accurate cost estimate, you need to delve into details. Answer C is tempting also, and possible, except we don't really know if the project in question can use perametric modeling . Answer D is incorrect because it takes the most time, but it is most accurate.