Which of the following testing techniques ensures that the software product…

Correct answer: Regression Testing.

Explanation: Regression testing is performed after changes such as bug fixes, enhancements, or maintenance to ensure that these changes have not introduced new defects and that previously working functionality still behaves as expected. It typically involves re-running existing test cases or automated test suites.

• Detects side effects: it catches defects introduced in areas not directly modified.

• Validates existing functionality: confirms previously passing tests still pass after changes.

• Supports automated regression suites for quick, repeatable verification after each change.

Why the other techniques are not the best fit:

• Path Testing focuses on executing control-flow paths within code modules and is aimed at thorough internal path coverage, not at re-verifying existing system behaviour after changes.

• Integration Testing checks interactions between modules and interfaces; it helps find integration issues but does not systematically re-run the broad set of existing tests to detect regressions.

• Unit Testing verifies individual components in isolation and is valuable for early defect detection, but it does not ensure the end-to-end product behaviour remains correct after maintenance.