The best approach is to use Terraform scripts while creating golden images (A). Terraform is an Infrastructure as Code (IaC) tool that allows organizations to automate infrastructure deployment consistently across environments. A golden image is a pre-configured, patched, and hardened system image used as a standard baseline. By creating golden images via Terraform scripts, the company ensures that every microservice instance is deployed on an already-updated and secure OS. This eliminates the need for repeatedly patching the base OS before code deployment.

Option B (cron job with apt-update) applies patches but introduces delays (every 30 days) and lacks consistency across new deployments. Option C (snapshots) saves deployment states but risks replicating outdated or unpatched images. Option D (centralized update server) is useful but still requires updates post-deployment, which slows the rollout of microservices.

By automating golden image creation through Terraform, the company gains efficiency, repeatability, and security assurance, aligning with DevSecOps principles and CAS-005 cloud-native best practices.