Comprehensive and Detailed Explanation From Exact Extract of ISTQB Certified Tester Advanced Level – Test Manager v3.0 syllabus:

In theTest Planningactivities of the CTAL-TM v3.0 syllabus (Chapter 3), the selection oftest design techniquesis part of defining thetest approach. The syllabus describes that when thetest manager defines the test approach, they determinehowtesting will be performed, including thetest design techniquesto be used, and align resources and estimates accordingly.

The earlier tasks in planning set the stage (understanding context and organization) and address risk treatment choices, while theestablish test plantask documents and baselines the already chosen approach and decisions.

Why the other options are incorrect:

A. Understand the context and organise test planning– This task focuses on analyzing the test context, stakeholders, constraints, and organizational aspects to prepare for planning; it does not yet select specifictest design techniques.

B. Identify risk treatment approaches– This task deals with how risks will be addressed (e.g., through mitigation, contingency, or targeted testing focus); it informs priorities but does not itself selecttest design techniques.

D. Establish test plan– This task records and baselines the plan (including approach and techniques already chosen). The selection of techniques has already occurred when defining the approach.

References (ISTQB Certified Tester Advanced Level – Test Manager v3.0 syllabus):

Chapter 3:Test Planning, Monitoring, and Control– subsection describingtest planning tasksand the activity todefine the test approach(which includes selectingtest design techniques), followed by estimation/resource allocation and subsequent establishment of thetest plan.