A company is building a two-tier web application to serve dynamic transaction-based content. Which services would you leverage to enable an elastic and scalable WEB TIER?

Answer options:

A.Elastic Load Balancing, Amazon EC2, and Auto Scaling
B.Elastic Load Balancing, Amazon RDS with Multi-AZ, and Amazon S3
C.Amazon RDS with Multi-AZ and Auto Scaling
D.Amazon EC2, Amazon Dynamo DB, and Amazon S3

Correct Answer – A
The question mentions a scalable Web Tier. So Option B, C, and D can be eliminated since they are database related options.
The below example ( this is a general depiction giving the deployment design of standby architecture having a two-tier in them ) shows an Elastic Load Balancer connected to 2 EC2 instances via Auto Scaling. This is an example of an elastic and scalable Web Tier. By scalable, we mean that the Auto Scaling process can increase or decrease the number of EC2 Instances as required.
For more information on the Elastic Load Balancer, please refer to the URL below.
https://docs.aws.amazon.com/elasticloadbalancing/latest/classic/introduction.html