You need your API backed by DynamoDB to stay online during a total regional AWS failure. You can tolerate a couple
minutes of lag or slowness during a large failure event, but the system should recover with normal operation after those
few minutes. What is a good approach?

A.
Set up DynamoDB cross-region replication in a master-standby configuration, with a single standby in another region. Create an Auto
Scaling Group behind an ELB in each of the two regions DynamoDB is running in. Add a Route53 Latency DNS Record with DNS
Failover, using the ELBs in the two regions as the resource records.

B.
Set up a DynamoDB Multi-Region table. Create an Auto Scaling Group behind an ELB in each of the two regions DynamoDB is
running in. Add a Route53 Latency DNS Record with DNS Failover, using the ELBs in the two regions as the resource records.

C.
Set up a DynamoDB Multi-Region table. Create a cross-region ELB pointing to a cross-region Auto Scaling Group, and direct a
Route53 Latency DNS Record with DNS Failover to the cross-region ELB.

D.
Set up DynamoDB cross-region replication in a master-standby configuration, with a single standby in another region. Create a crossregion ELB pointing to a cross-region Auto Scaling Group, and direct a Route53 Latency DNS Record with DNS Failover to the cross-
region ELB.

Explanation:
There is no such thing as a cross-region ELB, nor such thing as a cross-region Auto Scaling Group, nor such thing as a
DynamoDB Multi-Region Table. The only option that makes sense is the cross-regional replication version with two ELBs
and ASGs with Route53 Failover and Latency DNS.
http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Streams.CrossRegionRepl.html