Your website is hosted on 10 EC2 instances in five regions around the globe, with two instances per region. How could you configure your site to maintain availability with minimum downtime if one of the five regions was to lose network connectivity for an extended period?Choose the correct answer from the options given below.

Answer options:

A.Establish VPN connections between the instances in each region. Rely on BGP to failover in the case of region-wide connectivity failure for an extended period.
B.Create a Route 53 Latency Based Routing Record Set that resolves to an Elastic Load Balancer in each region and has the Evaluate Target Health flag set to true.
C.Create a 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 a Elastic Load Balancer to place in front of the EC2 instances. Set an appropriate health check on each ELB.

Answer – B
If your application is hosted on Amazon EC2 instances in multiple Amazon EC2 regions, you can reduce latency for your users by serving their requests from the Amazon EC2 region for which network latency is lowest. Amazon Route 53 latency-based routing lets you use DNS to route user requests to the Amazon EC2 region that will give your users the fastest response.
The Evaluate Target health check will ensure availability. If any one of the regions fails, since the evaluate target is set to true , the requests will be sent to another region.
For more information on latency based routing, please visit the link:
http://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy.html#routing-policy-latency