To answer this question, you need to understand black box testing and different design techniques used in software testing.
Black box testing is a testing technique where the internal workings of the system under test are not known to the tester. The tester focuses on the inputs and outputs of the system without considering its internal structure or implementation. Black box design techniques are used to define test cases for black box testing.
Let's go through each option to understand why it is correct or incorrect:
Option A) Statement testing - This option is incorrect because statement testing is a white box design technique. It involves testing individual statements or instructions in the code to ensure that they are executed correctly.
Option B) Equivalence partitioning - This option is correct because equivalence partitioning is a black box design technique. It involves dividing the input domain into equivalence classes and selecting test cases from each class to represent the entire input domain. This technique helps in reducing the number of test cases while still providing adequate coverage.
Option C) Error-guessing - This option is incorrect because error-guessing is not a specific design technique. It is a technique where testers use their experience and intuition to guess potential errors or issues in the system without following any specific design guidelines.
Option D) Usability testing - This option is incorrect because usability testing is not a design technique. It is a type of testing where the focus is on evaluating the system's user interface and user experience.
The correct answer is Option B) Equivalence partitioning. This option is correct because equivalence partitioning is a black box design technique used in black box testing.