Correct answer - "System will keep running as is" : You are already running at max capacity.
After you have created your Auto Scaling group, the Auto Scaling group starts by launching
enough EC2 instances to meet its minimum capacity (or its desired capacity, if specified). If
there are no other scaling conditions attached to the Auto Scaling group, the Auto Scaling group
maintains this number of running instances even if an instance becomes unhealthy.
"The desired capacity will go up to 4 and the maximum will stay at 3" - The desired capacity
cannot go over the maximum capacity
"The desired capacity will go up to 4 and the maximum will stay at 4" - The maximum capacity
cannot change on its own because the desired capacity has reached its limit. You will have to
make those changes manually
"System will trigger CloudWatch alarms to AWS support " - You already have alarms configured
based on rules but AWS support will not intervene for you. You are the admin of the settings AWS
allows you to change