What could be happening?

You have deployed a web application, targeting a global audience across multiple AWS Regions
under the domain name example.com.
You decide to use Route53 Latency-Based Routing to serve web requests to users from the
region closest to the user. To provide business continuity in the event of server downtime you
configure weighted record sets associated with two web servers in separate Availability Zones
per region. During a DR test you notice that when you disable all web servers in one of the
regions Route53 does not automatically direct all users to the other region.
What could be happening? Choose 2 answers

A.
You did not set “Evaluate Target Health” to ‘Yes” on the latency alias resource record set
associated with example.com in the region where you disabled the servers

B.
The value of the weight associated with the latency alias resource record set in the region with
the disabled servers is higher than the weight for the other region

C.
One of the two working web servers in the other region did not pass its HTTP health check

D.
Latency resource record sets cannot be used in combination with weighted resource record sets

E.
You did not setup an HTTP health check for one or more of the weighted resource record sets
associated with the disabled web servers

Explanation:
http://docs.aws.amazon.com/Route53/latest/DeveloperGuide/dns-failover-complex-configs.html
For both latency alias resource record sets, you set the value of “Evaluate Target Health” to Yes.
You use the Evaluate Target Health setting for each latency alias resource record set to make
Amazon Route 53 evaluate the health of the alias targets—the weighted resource record sets—
and respond accordingly.