In the newest version of payroll system number of changes were made.

Confirmation testing, also known as re-testing, is performed to verify that specific defects have been successfully fixed.

Option A: "Testing due to the application of a new version of the interface" would typically involve regression testing, not confirmation testing.

Option B: "Testing that fixes resolved the defects in the search function" fits the description of confirmation testing as it focuses on ensuring that specific issues have been addressed.

Option C: "Testing if a system still works after update of an operating system" is an example of regression testing, as it checks the overall system behavior after an update.

Option D: "Testing to ensure the adding of new functionalities haven't broken existing functions" is another example of re​ (ISTQB not-for-profit association)​​ (Udemy)​ it checks for unintended consequences of new changes.

Therefore, the correct answer is B【6†source】【9†source】.