You are designing multi-region architecture, and you want to send users to a geographic location based on latency-based routing, which seems simple enough. However, you also want to use weighted-based routing among resources within that region. Which of the below setups would best accomplish this?

Answer options:

A.You will need to use complex routing (nested recordsets) and ensure that you define the latency based records first.
B.You will need to use complex routing (nested recordsets) and ensure that you define the weighted resource record sets first.
C.This cannot be done. You can`t use different routing records together.
D.You will need to use AAAA - IPv6 addresses when you define your weighted based record sets.

Answer – B
Option A is incorrect because you need to define the recordset to be pointed to (in this case, weighted) before creating the top level recordset (in this case, latency).
Option B is CORRECT because you need to create the weighted policies first because you will use those record sets as the alias pointing to in the latency record sets.
Option C is incorrect because you can create the nested recordsets to accomplish this.
Option D is incorrect because the use of IPv6 is not mandatory in this configuration (and it does not mention any latency based routing - which is one of the requirements).
Please refer to the below documentation from AWS for an example where you can define complex routing.
Please find the below link for complex-based routing.
http://docs.aws.amazon.com/Route53/latest/DeveloperGuide/dns-failover-complex-configs.html