Anytime a company brings on a new employee, they want to ensure they meet their standards and align with their core values. Their reputation counts on the ethical consistency of every representative of their brand. Begin with sharing your values, ethics, and how the integrity of your brand aligns with that of Morgan Stanley. If you have an example where your ethicality and integrity were put to the test, share it. If you don't have an example, emphasize the value you place on your ethicality, and convey your values and the importance of the nature of the question.