You support a stateless web-based API that is deployed on a single Compute Engine instance in the europe-west2-a zone. The Service Level Indicator (SLI) for service availability is below the specified Service Level Objective (SLO). A postmortem has revealed that requests to the API regularly time out. The time outs are due to the API having a high number of requests and running out memory. You want to improve service availability. What should you do?

A. Change the specified SLO to match the measured SLI B. Move the service to higher-specification compute instances with more memory C. Set up additional service instances in other zones and load balance the traffic between all instances D. Set up additional service instances in other zones and use them as a failover in case the primary instance is unavailable