Your interviewer aims to gain insights into your work ethic and how diligent you are in ensuring your quality of work exceeds expectations. As they detail online, the European Investment Bank is looking for candidates with a "pro-active attitude and solution-oriented, continuous improvement and optimisation mindset" and an "ability to multi-task, prioritize, and manage time effectively." So walk your interviewer through your work standard and work ethic. Assure them that you are diligent when submitting your work and that, when possible, your standard aims to go the extra distance and exceed expectations.