A solutions architect is designing the cloud architecture of a new application being deployed onto AWS Cloud. This application has a set of instances that are required to be placed in a placements group. The instances should be placed on distinct racks, with each rack having its own network and power source.
Which of the following designs provides the highest availability for the application?

Answer options:

A.Place the instances into a cluster placement group that can span across multiple Availability Zones.
B.Place the instances into a partitions placement group to evenly distribute the instances across partitions in an availability zone.
C.Place the instances into a spread placement group that can span multiple Availability Zones in the same Region.
D.Place the instances into a spread placement group that can span multiple Availability Zones in the multiple Regions.

Answer: C
Cluster
Partition
Spread
Option A is incorrect because a cluster placement group cannot span across multiple Availability Zones, doesn`t meet HA requirements.
Option B is incorrect because the instances are placed in an availability zone. If this particular availability zone has an outage, the application will be impacted. As this question asks for the design with the highest availability, this option is not suitable.
Option C is CORRECT as this meets the HA requirement. See above diagrams. A spread placement group supports a maximum of seven running instances per Availability Zone. For example, in a Region with three Availability Zones, a total of 21 instances ( 7 x 3)in the group (seven per zone). If any plans to start the eighth instance in the same AZ and the same spread placement group, the instance will not launch.
Option D is incorrect because the spread placement group cannot span across multiple regions.
References:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html#concepts-placement-groups