Welcome to your interview.
The question is on your right: Acquisition and Retention Feature Test. 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.
You are testing a new product feature that could influence both top-of-funnel acquisition and downstream retention. The feature may make the product more appealing to new users, but it could also change the quality of users who sign up or alter early product experience in ways that affect whether they come back.
How would you design an experiment for this feature so you can measure its impact on both acquisition and retention? Explain how you would choose the primary metric, guardrails, randomization approach, and decision rule given that the feature affects multiple stages of the user journey.