An ecommerce company is migrating its on-premises workload to the AWS Cloud. The workload includes a web application and a backend Microsoft SQL database. The company expects a high customer volume during a promotional event. The new infrastructure must be highly available and scalable with the LEAST administrative overhead. Which solution meets these requirements?

This solution provides high availability and scalability with the least administrative overhead. An Auto Scaling group automatically adjusts the number of EC2 instances for the web application based on demand, ensuring scalability and high availability across multiple Availability Zones (AZs) behind an Application Load Balancer. Amazon RDS with Multi-AZ deployment automatically provisions and maintains a synchronous standby replica in a different AZ, providing high availability and automated failover for the database without manual intervention. The other options are less optimal. Migrating the database to two EC2 instances across separate AWS Regions with database replication increases administrative overhead significantly. Using RDS read replicas for high availability is incorrect; Multi-AZ is for high availability, while read replicas are for read scalability. Manually managing EC2 instances for the database, even across multiple AZs, increases administrative overhead compared to RDS Multi-AZ.