The scenario describes deploying an API to multiple CloudHub workers. This configuration is specifically designed for high availability and fault tolerance. CloudHub includes a load balancer that distributes incoming requests across all active workers. If a single worker fails (e.g., due to an out-of-memory exception), the load balancer detects the failure and automatically stops routing traffic to it. The remaining healthy workers continue to process requests, ensuring the API service remains available to consumers and preventing a complete service outage.

B: An API Manager outage during the initial deployment would prevent the API from being correctly configured and managed, leading to a deployment failure and thus an outage.

C: A major failure of the entire AWS region where the application is deployed would make all workers and the underlying infrastructure unavailable, causing a complete service outage.

D: The API's core function depends on the backend Order Management System. If this system is inaccessible, the API cannot process any requests successfully, resulting in a service outage.

1. MuleSoft Documentation, "CloudHub Architecture": This document explains that CloudHub applications can be deployed to one or more workers. The platform's load balancer routes external traffic to the Mule instances (workers) running the application. This inherent load balancing across multiple workers is the foundation for fault tolerance. (Reference: MuleSoft Docs > CloudHub > CloudHub Architecture > Application and Worker).

2. MuleSoft Documentation, "High Availability": This page explicitly states, "To make your application highly available, deploy it to two or more workers. If one worker goes down, the other worker is still active, and the load balancer redirects traffic to the active worker." This directly supports why the failure of a single worker (Option A) does not cause a service outage. (Reference: MuleSoft Docs > CloudHub > High Availability).

3. MuleSoft Documentation, "API Manager": API Manager is part of the control plane. While a running API can often survive a temporary control plane outage due to policy caching, an outage during deployment is critical and would prevent the API from being successfully deployed and started. (Reference: MuleSoft Docs > Anypoint Platform > API Manager).

4. MuleSoft Whitepaper, "Architecting for High Availability with Anypoint Platform": This paper discusses various failure domains. A regional AWS failure (Option C) and a backend system failure (Option D) are identified as critical dependencies that can cause outages if not mitigated by multi-region or proper backend HA strategies, which are outside the scope of a standard multi-worker CloudHub deployment.