The correct answer is escaped defects. Escaped defects are defects that make it through all checkpoints to production. Because its remediation will require a large amount of rework, testing, retesting, discovering any dependent code and
then repeating the testing process, escaped defects are the most costly type of defect. The other answers are incorrect because technical debt describes the code and solution that needs to be refactored or cleaned before product release;
run-away defects is not a valid term; failure mode is the description of the team’s attitude and habits in the project.