Correct answer - "Add an ElastiCache Cluster" : In order to provide a shared data storage for
sessions that can be accessible from any individual web server, you can abstract the HTTP
sessions from the web servers themselves. A common solution to for this is to leverage an
ElastiCache service offerings which is an In-Memory Key/Value store such as Redis and Memcached.
"Enable RDS read replicas" - Read-replicas syncs from the master database so there will be
inconsistencies in using this approach
"Enable Load Balancer stickiness" - With sticky sessions feature, it instructs the load balancer
to route repeated requests to the same EC2 instance whenever possible. It can be used but
ElastiCache is more scalable
"Use Elastic IP" - An Elastic IP is a way to give your server a static IP address but won't
really solve your issue with sessions