A company wants to restrict access to the content of a main web application using AWS authentication and to implement a serverless architecture for fewer than 100 users. The solution must integrate with the main web application, serve content globally, scale as the user base grows, and provide the lowest login latency cost-effectively. Which solution meets these requirements MOST cost-effectively?

The correct solution leverages Amazon Cognito for authentication, which is a fully managed, serverless identity service ideal for fewer than 100 users, offering cost-effective scalability and low login latency. Lambda@Edge integrates seamlessly with CloudFront to provide serverless authorization at the edge, minimizing latency and cost. Amazon CloudFront, a global content delivery network (CDN), serves the web application globally, caching content at edge locations for improved performance and reduced latency for users worldwide. Incorrect options: AWS Directory Service for Microsoft Active Directory is overkill and more expensive for fewer than 100 users, and an Application Load Balancer alone doesn't provide global content delivery like CloudFront. AWS Lambda for authorization without Lambda@Edge would process requests in a single region, increasing latency for global users, and S3 Transfer Acceleration is for accelerating S3 uploads/downloads, not serving a dynamic web application globally with low latency. AWS Directory Service is again too complex and costly. AWS Elastic Beanstalk is a platform for deploying web applications, but it doesn't inherently provide global content delivery or edge authorization like CloudFront with Lambda@Edge.