To reduce unavailability of a critical web service, which two solutions can be employed?

Utilizing a try/catch block when making requests is an effective solution to reduce the unavailability of a critical web service. This coding practice allows the application to gracefully handle error situations instead of failing outright when an unresponsive web service is called. By catching exceptions, the application can implement fallback mechanisms, retry logic, or provide alternative responses, which enhances the overall user experience and system resilience.

Option A, which involves updating the service for a faster response time, does not directly address issues related to service availability; it focuses instead on performance, which is a separate concern. Furthermore, increasing the timeout as suggested in option C may not solve the underlying issue of the web service being unavailable—longer timeouts might result in users waiting excessively without resolution. Lastly, the throwOnError attribute being set to true as presented in option D will actually lead to exceptions being thrown when an error occurs, potentially disrupting the service rather than allowing for a graceful handling of errors.

Therefore, the approach of incorporating a try/catch block aligns closely with best practices for managing external service interactions and enhancing robustness against service interruptions.