Comprehensive and Detailed Explanation From Exact Extract:

AWS CodeArtifact is a fully managed artifact repository service that supports popular package formats and can proxy downstream public repositories securely. It integrates seamlessly with both AWS Cloud and on-premises environments and stores artifacts in highly durable object storage (Amazon S3). CodeArtifact encrypts data at rest and in transit by default.

Because there is currently no routing between the on-premises data center and AWS, establishing a third-party software VPN appliance for connectivity provides secure communication without requiring complex AWS Direct Connect or multiple VPN setups.

This solution can be deployed quickly (within two weeks), is highly available, and meets encryption requirements. Using CodeArtifact eliminates the need to maintain third-party artifact servers, reducing operational overhead and improving reliability.

Options B, C, and D introduce higher complexity with AWS Direct Connect or multiple VPN connections and third-party software that increases deployment time and operational burden, which is against the requirement for rapid deployment and high operational efficiency.

Reference from AWS Official Documentation:

AWS CodeArtifact Overview:"CodeArtifact is a fully managed artifact repository service that makes it easy for organizations to securely store, publish, and share software packages used in their software development process."(AWS CodeArtifact Documentation)

Encryption in AWS CodeArtifact:"CodeArtifact encrypts data at rest and in transit by default."(AWS CodeArtifact Security)

VPN Appliance Deployment:"Software VPN appliances are commonly used for secure, encrypted connectivity between on-premises data centers and AWS."(AWS VPN Options)