正解:C
Cost-effective: The template specifies spot instances, which are cheaper than on-demand instances.
Highly available: Autoscaling is enabled with a minimum of 2 instances, ensuring redundancy.
Self-healing: Autoscaling ensures instances are replaced if they fail.
Secure: The firewall rules allow HTTPS (port 443) from any source for public access while restricting SSH (port 22) to only 192.168.0.0/24, preventing unrestricted administrative access.
This template aligns best with the requirements of a public-facing, secure, self-healing, and cost-effective website deployment.