A company is migrating applications to AWS and already uses Chef recipes for configuration management. The team wants to keep using their existing Chef recipes after moving to AWS with minimal operational effort. Which solution is the most operationally efficient and preserves use of Chef recipes?

AWS OpsWorks is the most operationally efficient solution because it is a configuration management service that supports Chef. OpsWorks allows you to create stacks and layers, which can then be configured to use existing Chef recipes for instance provisioning, application deployment, and configuration. This directly leverages the company's existing Chef assets with minimal refactoring. Using CloudFormation to create EC2 instances and install a Chef server is possible but requires significant operational overhead for managing the Chef server itself. CloudFormation with layers is not a direct service for Chef recipe deployment. Elastic Beanstalk with Docker is designed for application deployment within containers, not for managing infrastructure configuration with Chef recipes.