The correct answer is: Use Amazon CloudFront with signed URLs to control secure streaming access for authorized users.

Amazon CloudFront is a globally distributed content delivery network (CDN) that improves latency and scalability for delivering media to users across the globe. By pairing CloudFront with signed URLs or signed cookies, the company can ensure that only authenticated users can access premium content. Signed URLs provide time-limited access to specific content, enabling secure distribution while maintaining a seamless user experience on mobile devices.

The option Configure an IPsec VPN connection between mobile devices and the AWS environment to handle media streaming securely is impractical. VPNs are not designed to handle high-scale media delivery to millions of users. Managing VPN connections for such a wide user base is not scalable and would significantly increase complexity and cost.

The option Store the media in a public Amazon S3 bucket and use AWS KMS keys to control streaming access is insecure. Public S3 buckets expose content to everyone, and KMS only secures the data at restnot during transmission. This setup cannot enforce fine-grained access control for streaming.

The option Establish an AWS Client VPN connection between each mobile device and AWS to securely deliver content is also inefficient and not scalable. Client VPN is better suited for providing secure access to internal corporate applicationsnot for mass-scale content distribution to consumer mobile apps.

This question is important because it evaluates your understanding of secure, scalable media delivery solutions. When faced with content delivery requirements for large audiences, CloudFront combined with signed URLs is the standard approach for ensuring performance and access control.

A good trick for similar questions: If you see phrases like 'millions of users' and 'authorized access to content,' think CDN (CloudFront) plus access management (signed URLs or cookies). VPN solutions should raise a red flag when the user base is public or consumer-facing at scale.

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