Correct Answer: DIn this scenario, the 'app' attribute ('chrome.exe') is stable because it specifies the application in which the UI element exists. The application name typically does not change, unlike attributes such as 'idx', which is a dynamic index number that can change with each page load, and 'css-selector', which can change if the layout or structure of the webpage is altered. The 'title' attribute contains 'ACME System 1 [Development Environment]', which might change in different environments or with updates. Therefore, 'app' is the most reliable and stable attribute in this automatically-generated selector.