Which of the following is categorized as a black-box test technique?

The choice of a method based on formal requirements is categorized as a black-box test technique because it focuses on the specifications and requirements of the software without considering the internal workings or code of the application. Black-box testing involves evaluating the functionality of the software by providing inputs and observing the outputs, ensuring that the system behaves as expected according to predefined requirements.

This technique emphasizes validating whether the application meets the functional criteria laid out in the specifications, making it essential for understanding if the software fulfills its intended purpose from a user's perspective. It abstracts away any knowledge of the internal structures or algorithms, making it ideal for confirming if the system adheres to the expectations set forth in the formal requirements documentation.

In contrast, the other options are associated with different aspects of testing:

• Techniques based on architectural analysis would involve understanding the internal architecture to validate design components.
• Methods referring to technical design accuracy focus on how well the software design aligns with technical standards and practices.
• Techniques reliant on past fault knowledge typically leverage historical data to inform testing strategies but are not aligned with the principles of black-box testing, as they may require insights into previous defects and internal system behaviors.