The correct answer is B. Planning. This is because test metrics are quantitative measures that are used to monitor and control the test process, and to evaluate the test results and quality. Test metrics should be defined during the planning step of the Fundamental Test Process, which is the activity of establishing the test objectives, scope, approach, resources, schedule, and deliverables. By defining the methods to be used to collect test metrics during the planning step, the test team can ensure that the test metrics are aligned with the test plan and the project goals, and that the data collection process is consistent and efficient. Test Metrics - ISTQB not-for-profit association References: Certified Tester Advanced Level Test Manager (CTAL-TM) - ISTQB not-for-profit association, ISTQB Test Manager Certification - ISTQB Exams Worldwide - ISTQB Official Registration, Test Metrics - ISTQB not-for-profit association