What should a solutions architect recommend to meet these requirements?

Explanations:

Using Route 53 to distribute requests across two regions can provide redundancy, but it doesn’t ensure high availability and fault tolerance as effectively as an Auto Scaling group with an Application Load Balancer (ALB) within a single region. This setup may also introduce latency due to cross-region traffic.

This option provides a highly available and fault-tolerant architecture. An Auto Scaling group allows the application to automatically scale based on traffic demands, and an ALB distributes traffic across multiple EC2 instances in different Availability Zones, minimizing latency and enhancing fault tolerance.

A cluster placement group is designed for high throughput and low latency between instances but does not provide high availability across multiple Availability Zones. If an Availability Zone goes down, all instances in that placement group would be impacted.

While using an Auto Scaling group improves scalability, placing the instances in a cluster placement group limits high availability. If one Availability Zone fails, the entire application could become unavailable, which does not meet the fault tolerance requirement.