A social media company is building a feature for its website. The feature will give users the ability to upload photos. The company expects significant increases in demand during large events and must ensure that the website can handle the upload traffic from users. Which solution meets these requirements with the MOST scalability?

Generating Amazon S3 presigned URLs allows users to directly upload files to S3 without routing traffic through application servers. This offloads the upload burden from the application, making the solution highly scalable as S3 handles all the concurrency and throughput for uploads. Uploading files to application servers and then to S3 introduces a bottleneck at the application layer, limiting scalability. AWS Storage Gateway is primarily for hybrid cloud storage and is not designed for direct, high-volume user uploads from the internet. Amazon EFS is a network file system for EC2 instances and is not suitable for direct internet uploads from user browsers due to security and performance considerations.