Which solution meets these requirements?

Explanations:

Using theaws ec2 register-imagecommand to create an AMI from a snapshot does not provide minimum initialization latency. The process of registering an image and then waiting for the Auto Scaling group to replace the AMI is not optimal for rapidly provisioning instances under sudden demand. AWS Step Functions are not required for AMI management in this context.

Enabling Amazon EBS fast snapshot restore allows the snapshots to be ready for immediate use, significantly reducing the initialization latency when provisioning new instances from the AMI. This approach allows the Auto Scaling group to quickly replace the AMI with the newly provisioned AMI, effectively handling sudden increases in demand.

While Amazon Data Lifecycle Manager (DLM) can automate AMI creation, it does not directly address minimum initialization latency in an Auto Scaling context. The need to create a new AMI and then modify the Auto Scaling group can introduce delays, making this option less suitable for immediate demand spikes.

Amazon EventBridge is useful for triggering AWS Backup lifecycle policies, but this approach would not guarantee low initialization latency. The process of creating AMIs and managing Auto Scaling group capacity limits through event-driven policies does not provide the rapid provisioning needed for sudden demand increases.