Welcome to your interview.
The question is on your right: IPv6 vs IPv4 Need. 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.
Tell me about why you would need IPv6 over IPv4 and what tradeoffs matter in practice.