Determining the cost of external failures involves analyzing the impact of defects that escape into production.
This includes the direct costs associated with fixing the defects, as well as the indirect costs such as customer dissatisfaction, damage to the company's reputation, and potential loss of business. By quantifying these costs, the Test Manager can illustrate the financial benefits of comprehensive testing in preventing high-cost external failures, thereby demonstrating its value as an investment rather than a cost overhead.
References:The ISTQB Advanced Level Test Manager documents provide guidelines on how to establish and use metrics to measure the effectiveness and efficiency of the testing process, including the cost of quality and the Return on Investment (ROI) for testing activities. These references support the rationale behind choosing option C as the verified answer.