Which statement best describes the purpose of non-functional testing?

The purpose of non-functional testing is best captured by the statement that highlights its focus on measuring characteristics of a system that give an indication of how the system performs its functions. Non-functional testing evaluates aspects such as performance, usability, reliability, and security, which are crucial to the overall user experience but do not pertain directly to specific functionalities of the software.

By assessing attributes like response time under load or user accessibility features, non-functional testing provides insight into how well the system operates in real-world scenarios. This understanding can help identify potential bottlenecks or usability issues before the product is released, ensuring that it meets user expectations and operates effectively in its intended environment. In contrast, the other options relate to specific areas or standards that do not encompass the broader intent of non-functional testing alone.