Which test design technique is classified as a structure-based (white box) technique?

The classification of test design techniques into structure-based (white box) techniques means that these techniques involve an understanding of the internal workings of the software being tested. They focus on the code and its execution paths, often leading to a more thorough examination of the application's logic.

Statement testing is a clear example of a structure-based technique, as it involves executing each line of code at least once to ensure that all statements are tested. This approach ensures maximum coverage of the code and helps catch errors that may not be discovered through other types of testing. By focusing on individual statements, it allows testers to verify that each part of the program behaves as expected when executed.

In contrast, the other options, such as exploratory testing, decision table testing, and state transition testing, do not require knowledge of the internal structure of the software. Exploratory testing is more about experience and intuition to find defects, decision table testing focuses on combinations of input conditions rather than code structure, and state transition testing looks at the states an application can be in and the transitions between those states. None of these techniques rely on the visibility of code, which is the defining characteristic of white box methods.