You are working as a project manager on an in-house banking software project. To prevent rework and excessive find/fix/retest cycles, the following process has been put in place for resolving a defect once it is found in the test lab: 1. The assigned developer finds and fixes the defect, then creates an experimental build 2. A peer developer reviews, unit tests, and confirmation tests the defect fix on his/her desktop 3. A tester—usually the one who found the defect—confirmation tests the defect fix in the development environment 4. Once a day, a new release with all confirmed defect fixes included, is installed in the test environment 5. The same tester from step 3 confirmation tests the defect fix in the test environment Nevertheless, a large number of defects which the testers confirmed as fixed in the development environment (in step 3) are somehow failing confirmation testing in the test environment, with the resulting rework and cycle time outcomes. You have the highest confidence in your testers, and have ruled out mistakes or omissions in step 3. Which of the following is the MOST likely part of the process to check next?