Your question is Past Project That Best Prepared You. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
What class, internship, or past project has most prepared you for the practical challenges of this software engineering role? Walk me through one specific example, what you owned, the real constraints you faced, and what you learned that you would apply here.