Which of the following describes a common debugging strategy?

• A. Rerun the full test suite until the failure disappears.
• B. Guess the root cause based on memory from previous issues.
• C. Reproduce with a minimal test case; insert logs or use a debugger; isolate the problem with binary search on code paths.
• D. Only check the latest changelist for potential errors.

Answer: (C)

Reproducing a minimal failing case, instrumenting the run, and narrowing down with a binary search on the code paths is a reliable debugging strategy. Start by creating the smallest possible test scenario that still triggers the failure. This focused setup removes noise from unrelated parts of the system and makes the bug easier to observe and reproduce consistently. Next, add instrumentation—logs that capture key state, inputs, outputs, and progress, or use a debugger to inspect variable values and the execution path in real time. This visibility is essential for understanding how the code behaves as the failure occurs. Finally, isolate the problem by systematically narrowing the code paths or changes involved. Treat it like a binary search: pick a suspect region, verify whether the failure still happens, then move to a smaller region based on the result, repeating until you locate the exact cause. This approach is efficient and evidence-driven, guiding you from a symptom to a specific defect. Rerunning the full test suite until the failure disappears can be wasteful and may not reveal the root cause, while guessing from memory or focusing only on the most recent change risks missing important interactions or earlier bugs.