Circuit breakers and bulkheads

A recommendations service is timing out on every call after 2 s. A breaker in front of it opens. What changes for the product page that calls it?

A dependency has ten replicas behind client-side load balancing. One replica starts failing every request, which is 10% of calls overall. Your breaker opens at a 50% failure rate. What is the best setup?

A checkout service calls payments, inventory and recommendations from one shared thread pool. Recommendations starts hanging. Which changes keep checkout working? Select all that apply.