Welcome to your interview.
The question is on your right: Optimize a Large Data Workflow. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
A large pipeline already produces correct outputs, but runtime and cost are too high. You need to improve efficiency without changing business logic, output definitions, or downstream expectations.