Which of the following outlines the levels of testing?

The answer is based on the established levels of testing commonly recognized in software development. Unit testing, integration testing, system testing, and acceptance testing represent a structured approach that breaks down the testing process into clear, defined stages.

Unit testing is the first level and focuses on individual components or functions within the software to ensure they work as intended in isolation. Following that, integration testing examines how these individual units interact with one another, checking for issues that may arise when they are combined.

System testing takes this a step further by testing the complete and integrated software system to evaluate its compliance with the specified requirements. Finally, acceptance testing is conducted to determine whether the software meets the acceptance criteria set by stakeholders and is ready for deployment to the end users.

This framework is pivotal in ensuring comprehensive coverage of the software's functionality and helps in identifying defects early in the development cycle. By delineating these levels, teams can manage testing efforts effectively, ensuring that each aspect of the software is thoroughly evaluated before reaching the end users.