What AWS services should be used meet these requirements?

A read only news reporting site with a combined web and application tier and a database tier that receives large and unpredictable traffic demands must be able to respond to these traffic fluctuations automatically.

What AWS services should be used meet these requirements?
A . Stateless instances for the web and application tier synchronized using ElastiCache Memcached in an autoscaimg group monitored with CloudWatch and RDS with read replicas.
B . Stateful instances for the web and application tier in an autoscaling group monitored with CloudWatch and RDS with read replicas.
C . Stateful instances for the web and application tier in an autoscaling group monitored with CloudWatch and multi-AZ RD
E . Stateless instances for the web and application tier synchronized using ElastiCache Memcached in an autoscaling group monitored with CloudWatch and multi-AZ RD

Answer: A