Option A is correct because it addresses the need for geographical redundancy by replicating VMs in another zone (us-central1-b) and using a load balancer to distribute traffic, ensuring high availability at minimal cost in case of zonal failure. Option B is incorrect as it lacks redundancy outside the us-central1-a zone. Option C is incorrect because it doesn't provide zonal redundancy. Option D is incorrect as backups don't offer immediate availability during a zonal failure. Choosing the right region and zone is crucial for your scenario, as detailed in GCP documentation.