QuickDialog is a multimedia company running a messaging app. One of the principal features of QuickDialog is that pictures and messages are usually only available for a short time before they become inaccessible to users. The app has evolved from originally centering on person-to-person photo sharing to present users` "Stories" of 24 hours of sequential content, along with "Discover", allowing brands show ad-supported short-form media.
They use DynamoDB to support the mobile application and S3 to host the images and other documents shared between users. KindleYou has a large customer base spread across multiple geographic areas. Customers need to update their profile information while using the application. Team understands the Global tables are the right solution to implement replication. If you perform 10 writes to a local table that is replicated in two additional Regions, how many WCU’s will be consumed? Select 1 option.

Answer options:

A.30 WCU’s
B.40 WCU’s
C.60 WCU’s
D.80 WCU’s

Answer: C
1 local +2 replica = 10+10+10=30,30X2 = 60
Using DynamoDB auto scaling is the recommended way to manage throughput capacity settings for replica tables that use the provisioned mode. DynamoDB auto scaling automatically adjusts read capacity units (RCUs) and write capacity units (WCUs) for each replica table based upon your actual application workload. For more information, see Managing Throughput Capacity Automatically with DynamoDB Auto Scaling.
If you create your replica tables using the AWS Management Console, auto scaling is enabled by default for each replica table, with default auto scaling settings for managing RCUs and WCUs.
Changes to auto scaling settings for a replica table or secondary index made through the DynamoDB console or using the UpdateGlobalTableSettings call are applied to all of the replica tables and matching secondary indexes in the global table automatically. These changes will overwrite any existing auto scaling settings. This ensures that provisioned write capacity settings are consistent across the replica tables and secondary indexes in your global table. If you use the UpdateTable, RegisterScalableTarget, or PutScalingPolicy calls, you should apply the change to each replica table and matching secondary index individually.
Note:
If auto scaling doesn`t satisfy your application`s capacity changes (unpredictable workload) or if you don`t want to configure its settings (target settings for minimum, maximum, or utilization threshold), you can use on-demand mode to manage capacity for your global tables. For more information, see On-Demand Mode.
If you enable on-demand mode on a global table, your consumption of replicated write request units (rWCUs) will be consistent with how rWCUs are provisioned. For example, if you perform 10 writes to a local table that is replicated in two additional Regions, you will consume 60 write request units (10 + 10 + 10 = 30; 30 x 2 = 60).
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/globaltables_reqs_bestpractices.html