When a lot of data exist about the effort required for project activities, thebottom-upestimation technique (D) is most appropriate. This method involves estimating the effort for each task in theWork Breakdown Structure (WBS)individually, then aggregating them to derive the total project duration or cost. It leverages detailed data for accuracy, as perPMBOK’s estimation techniques.

Top-down (A):Uses high-level estimates based on historical data or expert judgment, less accurate with detailed task data available.

Three-point (B):Uses optimistic, pessimistic, and most likely estimates for uncertainty, but is less focused on leveraging detailed effort data.

Comparative (C):Likely refers to analogous estimation, which relies on comparisons to past projects, not detailed task data.

Bottom-up estimation is ideal when detailed effort data is available, ensuring precision in project planning.