A multi-node Windows legacy application uses a network share as a central repository for .xml configuration files. The company is migrating the application to EC2 and needs a highly available configuration repository at minimal cost. Which solution is the MOST cost-effective way to provide a highly available repository for the configuration files?

The most cost-effective and highly available solution is to use Amazon S3. S3 offers high durability and availability by default, eliminating the need for complex HA setups. Using the AWS SDK allows direct application integration, which is efficient and leverages S3's native capabilities. Attaching an EBS volume to a single EC2 instance creates a single point of failure and requires manual HA configuration, increasing cost and complexity. An instance-store volume is ephemeral and not suitable for persistent data. Mounting an S3 bucket as a local filesystem (e.g., using S3 FUSE) is generally not recommended for production applications due to performance overhead and potential consistency issues, and it adds an unnecessary layer of abstraction compared to using the SDK directly.