Which option is the most cost effective and uses EC2 ca…

To serve Web traffic for a popular product your chief financial officer and IT director have purchased 10 ml
large heavy utilization Reserved Instances (RIs) evenly spread across two availability zones: Route 53 is used
to deliver the traffic to an Elastic Load Balancer (ELB). After several months, the product grows even more
popular and you need additional capacity. As a result, your company purchases two C3.2xlarge medium
utilization Ris. You register the two c3 2xlarge instances with your ELB and quickly find that the ml large
instances are at 100% of capacity and the c3 2xlarge instances have significant capacity that’s unused.
Which option is the most cost effective and uses EC2 capacity most effectively?

A.
Configure Autoscaling group and Launch Configuration with ELB to add up to 10 more on-demand m1.large
instances when triggered by Cloudwatch. Shut off c3.2xlarge instances.

B.
Configure ELB with two c3.2xlarge instances and use on-demand Autoscaling group for up to two additional
c3.2xlarge instances. Shut off m1.large instances.

C.
Route traffic to EC2 m1.large and c3.2xlarge instances directly using Route 53 latency based routing and
health checks. Shut off ELB.

D.
Use a separate ELB for each instance type and distribute load to ELBs with Route 53 weighted round robin.