Correct Answer: Option 4

Option 4 is the best and most cost-effective solution. Migrating the database to Amazon Aurora MySQL offloads database load from the EC2 instance and provides scalability, high availability, and performance improvements. Creating an AMI and using it in a launch template allows for consistent deployment of your application. Configuring an Auto Scaling group with Spot Instances helps minimize cost while allowing the application to scale out during peak traffic. Attaching an Application Load Balancer ensures traffic is routed to healthy instances, enabling seamless horizontal scaling and improved availability.

Why the other options are incorrect:

Option 1: Functional but less cost-effective due to the use of On-Demand EC2 instances and lack of dynamic scaling.
Option 2: Route 53 weighted routing lacks health checks and scaling flexibility compared to an ALB. It doesn't adapt automatically to changes in traffic.
Option 3: Using a Lambda to resize an EC2 instance introduces downtime, doesn't offer high availability, and doesnt support horizontal scaling.

Why this question is challenging: It tests knowledge of AWS scaling strategies, EC2 cost models, database decoupling, and elasticity using Auto Scaling groups and Spot Instances.

Full AWS Practitioner Certification Question