Stress testing is a type of performance testing that evaluates how a system behaves under extreme load conditions, such as high volume of data, concurrent users, or transactions12. Stress testing can help to identify the system’s breaking point, bottlenecks, and resource limitations, and to ensure that the system can recover from failures and maintain its functionality34. In this case, the team performed stress testing to validate that system performance will not be impacted by migrating all data to a single system following the merger of two companies. This implies that the team simulated a high amount of data transfer and processing, and measured the system’s response time, throughput, availability, and reliability under such load. Stress testing is better than the other options because:

Regression testing is a type of functional testing that verifies that a system’s existing features and functionality are not affected by a change or an update56. Regression testing does not focus on system performance or load conditions, but rather on system correctness and quality.

Smoke testing is a type of functional testing that checks the basic functionality and stability of a system before performing more detailed and comprehensive testing78. Smoke testing does not measure system performance or load conditions, but rather ensures that the system is ready for further testing.

Automation testing is a technique of using software tools or scripts to execute test cases and compare the actual results with the expected results910. Automation testing is not a specific type of testing, but rather a way of performing testing. Automation testing can be applied to various types of testing, including stress testing, regression testing, and smoke testing.

References = CompTIA Project+ Certification Study Guide, CompTIA Project+ Certification Exam Objectives, What is Stress Testing?1, Stress Testing: A Complete Guide2, What is Regression Testing?3, Regression Testing: A Complete Guide4, What is Smoke Testing?5, Smoke Testing: A Complete Guide6, What is Automation Testing?7, Automation Testing: A Complete Guide8