You are a Devops engineer for your company. The company hosts a web application that is hosted on a single EC2 Instance. The end users are complaining of slow response times for the application. Which of the following can be used to effectively scale the application?

Answer options:

A.Use Autoscaling Groups to launch multiple instances and place them behind an ELB.B.Use Autoscaling launch configurations to launch multiple instances and place them behing an ELB.C.Use Amazon RDS with the Multi-AZ feature.
D.Use Cloudformation to deploy the app again with an Amazon RDS with the Multi-AZ feature.

Answer - A
The AWS Documentation mentions the below
When you use Auto Scaling, you can automatically increase the size of your Auto Scaling group when demand goes up and decrease it when demand goes down. As Auto Scaling adds and removes EC2 instances, you must ensure that the traffic for your application is distributed across all of your EC2 instances. The Elastic Load Balancing service automatically routes incoming web traffic across such a dynamically changing number of EC2 instances. Your load balancer acts as a single point of contact for all incoming traffic to the instances in your Auto Scaling group.
For more information on Autoscaling and ELB, please refer to the below link:
http://docs.aws.amazon.com/autoscaling/latest/userguide/autoscaling-load-balancer.html