A Corporate Website Is Hosted on Several Amazon EC2 Instances

Multiple Choice

A corporate website is hosted on several Amazon EC2 instances across multiple regions around the globe. How should an Administrator configure the website to maintain high availability with minimal downtime if one of the regions has network connectivity congestion for an extended period of time?

A) Create an Elastic Load Balancer in front of all the Amazon EC2 instances.
B) Create an Elastic Load Balancer that fails over to the secondary site when the primary site is not reachable.
C) Create an Amazon Route 53 Latency Based Routing Record Set that resolves to an Elastic Load Balancer in each region. Set an appropriate health check on each ELB.
D) Create an Amazon Route 53 latency Based Routing Record Set that resolves to Elastic Load Balancers I each region and has the Evaluate Target Health flag set to "true".