Continuous integration is the correct answer. Continuous integration gives far more tests per day than the other options, with less time passed before identification of a problem. Daily build and smoke tests don’t shorten defect resolution;
this answer is incorrect. Usability testing is incorrect because it requires planning and participation to test the software. Exploratory testing is also incorrect because it allows testers to explore and test different facets of the
software. Continuous integration is done several times throughout the day.