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 Duration Estimating process according to the PMBOK Guide?

Introduction / Context:
Activity Duration Estimating called Estimate Activity Durations in later PMBOK editions is the Project Time Management process that estimates the number of work periods needed to complete individual activities. Accurate duration estimates are necessary for building a realistic schedule and for later performing schedule risk analysis. Knowing the key inputs, tools and techniques, and outputs for this process is a common PMP exam requirement.

Given Data / Assumptions:

• The knowledge area is Project Time Management.
• The process is Activity Duration Estimating.
• We want one representative input, one tool or technique, and one primary output.
• Activity list and activity resource requirements already exist from prior planning steps.
• The goal is to estimate how long each activity will take with the assigned resources.

Concept / Approach:
Activity Duration Estimating uses inputs such as activity list, activity attributes, activity resource requirements, resource calendars, and assumptions about resource productivity. A widely cited tool and technique is three point estimating, which uses optimistic, most likely, and pessimistic estimates to calculate an expected duration and understand uncertainty. The primary output is activity duration estimates, which state the expected time required to complete each activity and may include range information or confidence levels.

Step-by-Step Solution:
Step 1: Choose a logical input. Activity resource requirements are crucial because the type and amount of resources assigned influence how long an activity will take. Step 2: Identify an appropriate tool or technique. Three point estimating is commonly associated with duration estimating and is explicitly listed as a technique in PMBOK. Step 3: Select the primary output. Activity duration estimates are the direct result of performing this analysis for each activity. Step 4: Compare the options and choose the combination activity resource requirements, three point estimating, and activity duration estimates. Step 5: Check that other options are clearly from cost, quality, scope, or human resource processes rather than duration estimating.

Verification / Alternative check:
PMBOK style tables for Estimate Activity Durations show inputs such as activity list, activity attributes, activity resource requirements, resource calendars, project scope statement, risk register, and resource breakdown structure. Tools like expert judgment, analogous estimating, parametric estimating, three point estimating, reserve analysis, and decision analysis are listed. Outputs include activity duration estimates, project document updates, and updates to assumptions. This strongly supports the pattern used in the correct answer.

Why Other Options Are Wrong:
Option B clearly refers to cost control rather than duration estimating. Option C uses quality control techniques. Option D describes scope definition activities. Option E deals with acquiring the project team, not estimating how long activities will last.

Common Pitfalls:
Many learners confuse duration estimating with effort estimating, assuming that hours of work directly translate into duration without considering resource availability. Another pitfall is to associate earned value analysis with all estimating processes, although it is primarily used in performance measurement and forecasting. For the exam, remember that Activity Duration Estimating uses resource information and time based techniques like three point estimating to produce activity duration estimates.

Final Answer:
The correct ITTO combination for Activity Duration Estimating is activity resource requirements; three point estimating; activity duration estimates.