Which role does 'testing' play in ensuring software quality?

Testing plays a crucial role in ensuring software quality by finding and resolving defects before the software is released to users. The primary goal of testing is to verify that the software functions as intended and meets the specified requirements. Through various testing methodologies, such as unit tests, integration tests, system tests, and acceptance tests, developers and quality assurance teams systematically identify issues, bugs, and inconsistencies in the code.

By addressing these defects during the testing phase, developers can improve the reliability, performance, and usability of the software, ultimately leading to a better user experience and fewer problems in production. This proactive approach helps mitigate the risk of failures that could arise if the software was released without thorough testing.

In contrast, the other options refer to aspects that are not directly linked to the testing process in software development—such as marketing strategies, user experience design, or algorithm development—which do not play a role in identifying defects in the software itself.