The correct answer isBbecause the company explicitly wants to move from amonolithic architectureto aloosely coupled architecturethat supportsindependent scaling. Refactoring the application intomicroservicesis the architectural approach that best meets that requirement. Running the microservices onAmazon ECScontainers provides a managed container orchestration platform with less operational overhead than managing a Kubernetes environment.

With microservices, separate business functions such as product catalog management and customer checkout can be deployed as individual services. Each service can scale independently based on its own traffic and performance characteristics. This is far more efficient than scaling the entire monolithic application when only one part of the system experiences increased demand.

AnApplication Load Balanceris appropriate because it can route HTTP and HTTPS traffic and supports path-based and host-based routing, which is useful for directing requests to different services. This design improves agility, performance, and operational flexibility while supporting the company’s need for growth.

Option A improves availability and scalability, but it still runs a copy of thesame monolithic applicationon multiple EC2 instances. That does not enable independent scaling of individual functions. Option C creates a basic two-tier design, but it is not a fully loosely coupled microservices architecture. Option D uses Amazon EKS but places the application into asingle container, which does not achieve independent scaling of separate components and introduces more operational complexity than necessary.

AWS architectural best practices recommend decomposing monoliths intomicroserviceswhen independent scaling, agility, and component isolation are required. Therefore,Amazon ECS with microservicesis the best solution.