AWS Technical Essentials Practice

Elastic Load Balancing is the correct choice for ensuring high availability for applications deployed in multiple regions. This service automatically distributes incoming application traffic across multiple targets, such as Amazon EC2 instances, containers, and IP addresses. By balancing the load over numerous instances spread across different regions, Elastic Load Balancing can maintain application performance and availability even if one of the instances or a whole region experiences issues.

It supports both regional and global load balancing through the use of Network Load Balancers and Application Load Balancers, giving flexibility to manage traffic effectively across multiple locations. This ability to distribute traffic and maintain service availability is crucial for applications that aim for resilience against failures and seamless user experience.

The other services mentioned do not inherently provide the same level of availability when it comes to application traffic management across multiple regions. For example, while Amazon EC2 provides a compute resource, it does not by itself ensure high availability without additional configurations. Amazon RDS focuses on managing relational databases and does include some features for high availability, but its primary role is not load balancing global traffic. Amazon S3 is a storage service and ensures high durability and availability for data but does not directly manage application traffic across regions like Elastic Load Balancing does.