Correct answer - "all at once" : Deploy the new version to all instances simultaneously and hence
the shortest time. All instances in your environment are out of service for a short time while
the deployment occurs.
"rolling" - Deploys the new version in batches. Each batch is taken out of service during the
deployment phase, reducing your environment's capacity by the number of instances in a batch
"rolling with additional batches" - Deploys the new version in batches, but first launch a new
batch of instances to ensure full capacity during the deployment process
"immutable" - Deploys the new version to a fresh group of instances by performing an immutable
update
"blue/green" - With this strategy you deploy the new version to a separate environment, and then
swap CNAMEs of the two environments to redirect traffic to the new version instantly.