Which AWS service can manage large-scale containerized applications effectively?

Amazon Elastic Container Service (ECS) is the correct choice for managing large-scale containerized applications effectively. ECS is specifically designed to handle the orchestration and deployment of containerized applications. It provides features such as scaling, load balancing, and service discovery out of the box, making it well-suited for running applications in a large-scale environment.

By utilizing ECS, organizations can easily deploy and manage their applications in an agile manner, leveraging containers for greater flexibility and efficiency. Additionally, it integrates seamlessly with other AWS services, allowing for a cohesive cloud-based infrastructure.

The other options, while powerful in their own right, serve different purposes. AWS Batch is designed primarily for running batch processing jobs at scale rather than managing containerized applications directly. Amazon EC2 provides virtual server instances to run applications but does not offer the container orchestration features that ECS does. AWS Lambda is a serverless computing service meant for running code in response to events and is not focused on managing containerized applications either.