Thank you Avni!Not a competency-style question. They're asking this to get to know who you are, not why you're suitable candidate for a graduate opportunity at the firm.
I would mention the traits and experiences I've had outside of the training contract application process to answer this question.
Bringing up your interests, your background (cultural, educational etc.), your motivations, USP and how you occupy yourself outside of making applications will help make your answer stand out.
Wishing you the best!