What kind of tests can SoapUI perform?

SoapUI is a versatile testing tool specifically designed for testing web services and APIs. The correct assertion highlights its capability to conduct functional testing, load testing, and compliance testing.

Functional testing allows users to verify that web services or APIs are performing their intended functions as expected. This is essential for ensuring that the application behaves correctly from the end user's perspective. Load testing, on the other hand, is focused on determining how well a service performs under various levels of load, which is vital for understanding scalability and performance characteristics. Compliance testing is performed to ensure that the web services adhere to specific standards and regulations, which is critical in regulated industries or for applications that must meet certain compliance requirements.

The other options suggest a narrower scope of testing. For example, limiting testing to only unit tests or focusing exclusively on security would not leverage the full capabilities of SoapUI, as it is designed to handle a variety of testing types applicable to web services comprehensively. Hence, the answer correctly captures SoapUI's broad range of testing capabilities.