Welcome to your interview.
The question is on your right: Recursion and Optimal Use. 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.
Explain the process of recursion and provide an example of when it is the optimal approach.