AWS Certified Solutions Architect - Professional (#290)

A company has an Amazon EC2 deployment that has the following architecture:

An application tier that contains 8 m4.xlarge instances

A Classic Load Balancer

Amazon S3 as a persistent data store

After one of the EC2 instances fails, users report very slow processing of their requests. A Solutions Architect must recommend design changes to maximize system reliability. The solution must minimize costs. What should the Solution Architect recommend?

Migrate the existing EC2 instances to a serverless deployment using AWS Lambda functions
Change the Classic Load Balancer to an Application Load Balancer
Replace the application tier with m4.large instances in an Auto Scaling group
Replace the application tier with 4 m4.2xlarge instances