You manage a microservice that provides a public-facing API (Service A). Service A is time-critical and has a response SLO of 500 ms. Service A makes synchronous calls to internal API (Service B) that is known to become unreliable under heavy load, resulting in connection timeout errors or 500 errors. Service B is used to collect request information for the transactions processed by Service A. You need to mitigate the impact of Service B issues on your Service A users. What should you do?

A. Increase the size of the queue in front of the thread pool used by Service A instances. B. Implement retry logic with exponential back-offs when calling Service B. C. Implement a circuit breaker to store the request data in a database. D. Implement rate limiting in Service A to limit the number of requests to Service B.