This question asks for a non-functional aspect of testing the download process of a mobile application. Option A, "It was easy to locate, download and install the application," refers to usability, which is a non-functional quality attribute. Non-functional testing involves testing the system's attributes, such as usability, performance, reliability, etc., rather than specific behaviors or functions. Options B, "The application was correctly downloaded," C, "The application created an installation log file in a given folder," and D, "The application installed only after the user's approval," describe functional aspects, focusing on what the software does rather than how it performs or is experienced by the user.