Which is the MOST cost-efficient and scalable deployment that will resolve the issues for users?

Explanations:

While enabling maximum I/O on EFS may improve performance, it does not address the root cause of buffering and timeout issues related to high traffic.

Using instance store volumes does not provide durability and scalability. The complexity of copying data on launch and shutdown is not cost-efficient.

Using Amazon CloudFront to distribute videos from S3 reduces latency and offloads traffic from the web application, providing a scalable and cost-efficient solution.

Pointing CloudFront at the ALB may help with some caching, but it does not specifically address the video content optimization, which is crucial for resolving buffering issues.