A company is developing a multi-tier web application to be deployed on the cloud. The application should be able to scale based on demand and protect against common web exploits. What architecture would BEST meet these requirements?
Deploying instances across multiple Availability Zones without mentioning any scalability measures or security services
Creating an auto-scaling group and an Elastic Load Balancer without integrating a security service
Deploying instances in an auto-scaling group, distributing traffic with an Elastic Load Balancer, and using a Web Application Firewall for protection
Launching all instances within a public subnet to maintain high availability and manual scaling on demand