A marketing research company has developed a tracking system that collects user behavior during web marketing campaigns on behalf of customers worldwide. The tracking system consists of an Auto Scaling group of EC2 instances behind an ELB. And the collected data is stored in DynamoDB. After the campaign is terminated, the tracking system is torn down, and the data is moved to Amazon Redshift, where it is aggregated and used to generate detailed reports.

Answer options:

A.Avoid using Deletion Policies for the EBS snapshots.
B.The names of the DynamoDB tables must be different in every target region.
C.Use the built-in function of Cloudformation to set the AZ attribute of the ELB resource.
D.IAM users with the right to start Cloudformation stacks must be defined for every target region.
E.Use the built-in Mappings and FindInMap functions of AWS Cloudformation to refer to the AMI ID set in the ImageID attribute of the Autoscaling::LaunchConfiguration resource.

Answer – C and E
Option A is incorrect because you need to retain or keep the snapshots of the EBS volumes to launch similar instances in the new region.
Option B is incorrect because a DynamoDB table with the same name can be created in different regions. They have to be unique in a single region.
Option C is CORRECT because you need to get the name of the Availability Zone based on the region in which the template would be used.
Option D is incorrect because you do not need to define IAM users per region as they are global.
Option E is CORRECT because the AMI ID would be needed to launch similar instances in the new region where the template would be used. 
More information on CloudFormation intrinsic functions:
You can use the Fn::GetAZs function of CloudFormation to get the AZ of the region and assign it to the ELB.An example of the Fn::GetAZs function is given below
{ "Fn::GetAZs" : "" }
{ "Fn::GetAZs" : { "Ref" : "AWS::Region" } }
{ "Fn::GetAZs" : "us-east-1" }
An example of the FindInMap is shown below. This is useful when you want to get particular values region wise which can be used as parameters. Since the Launch configuration contains the AMI ID information and the AMI ID is different in different regions, you need to recreate the Launch Configurations based on the AMI ID.{
...
"Mappings" : {
"RegionMap" : {
 "us-east-1" : { "32" : "ami-6411e20d", "64" : "ami-7a11e213" },
 "us-west-1" : { "32" : "ami-c9c7978c", "64" : "ami-cfc7978a" },
 "eu-west-1" : { "32" : "ami-37c2f643", "64" : "ami-31c2f645" },
"ap-southeast-1" : { "32" : "ami-66f28c34", "64" : "ami-60f28c32" },
"ap-northeast-1" : { "32" : "ami-9c03a89d", "64" : "ami-a003a8a1" }
}
},
"Resources" : {
 "myEC2Instance" : {
"Type" : "AWS::EC2::Instance",
"Properties" : {
 "ImageId" : { "Fn::FindInMap" : [ "RegionMap", { "Ref" : "AWS::Region" }, "32"]},
 "InstanceType" : "m1.small"
}
 }
 }
}
For more information on the Fn::FindInMap function, please refer to the below link-
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference.html
http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-findinmap.html