In Project Time Management, which of the following combinations correctly identifies a typical input, a tool or technique, and a primary output of the Activity Resource Estimating process according to the PMBOK Guide?

Introduction / Context:
The Activity Resource Estimating process known as Estimate Activity Resources in later PMBOK editions is part of Project Time Management. It focuses on determining the type and quantities of resources people, equipment, materials needed to perform each schedule activity. Correctly understanding the ITTOs for this process is important because it links scope and schedule to both human and physical resource planning.

Given Data / Assumptions:

• The knowledge area is Project Time Management.
• The process in focus is Activity Resource Estimating.
• We seek one representative input, one tool or technique, and one primary output.
• An activity list and activity attributes already exist from previous planning steps.
• The aim is to identify resource types and quantities for each activity.

Concept / Approach:
Activity Resource Estimating takes the activity list and the activity attributes as key inputs, along with resource calendars, enterprise environmental factors, and organizational process assets. A commonly cited tool and technique is alternative analysis, where different resource options are compared for cost, availability, and capability for example, using more people for less time versus fewer people for longer. The primary output is activity resource requirements, which specify what resources and how many units of each are needed for each activity. This output will later feed both cost estimating and schedule development.

Step-by-Step Solution:
Step 1: Select a logical input. The activity list is fundamental because you cannot estimate resources for activities that have not been defined. Step 2: Identify a suitable tool or technique. Alternative analysis is used to evaluate different ways of accomplishing the work with various resource combinations. Step 3: Define the primary output. Activity resource requirements describe the type and quantity of resources needed per activity. Step 4: Among the choices, pick the set that includes activity list, alternative analysis, and activity resource requirements. Step 5: Confirm that the other options refer to cost, scope, quality, or verification processes instead of resource estimation.

Verification / Alternative check:
Reference tables for Estimate Activity Resources in the PMBOK Guide show activity list, activity attributes, resource calendars, and risk register as inputs. Tools and techniques include expert judgment, alternative analysis, published estimating data, bottom up estimating, and project management software. Outputs include activity resource requirements, resource breakdown structure, and project document updates. This matches the pattern used in the correct option.

Why Other Options Are Wrong:
Option B deals with cost control and forecasting, not estimating resources for activities. Option C belongs to scope verification. Option D describes scope definition and WBS creation. Option E focuses on quality assurance, including audits and process improvement, rather than resource estimating.

Common Pitfalls:
A common error is to confuse activity resource estimating with cost estimating, assuming that both are part of the same process. While they are closely linked, resource estimating focuses on what and how many resources are needed, whereas cost estimating attaches monetary values to those resources. Another pitfall is ignoring non human resources, such as equipment and materials, when thinking about resource requirements.

Final Answer:
The correct ITTO combination for Activity Resource Estimating is activity list; alternative analysis; activity resource requirements.