Your organization had created an S3 bucket for static website hosting. They had created and configured all necessary components for the static website with the S3 website endpoint http://example-bucket.com.s3-website-us-east-2.amazonaws.com. They would like to get the website served through the domain name www.example-bucket.com which is already registered. You want to create a record in Route 53 to route to the S3 website endpoint. Which type of record set you need to create?

Answer options:

A.A - IPv4 Address with Alias=NO
B.A - IPv4 Address with Alias=YES
C.CNAME - Canonical Name with ALIAS=NO
D.CNAME - Canonical Name with ALIAS=YES

Answer: B
AWS Documentation:
https://docs.aws.amazon.com/AmazonS3/latest/dev/website-hosting-custom-domain-walkthrough.html#root-domain-walkthrough-s3-tasks
We can`t create a CNAME record for the Parent, Naked, or Apex domain, whereas we can use an alias record to point to the parent domain.
Below scenarios given are not possible.
www.example-bucket.com CNAME http://example-bucket.com.s3-website-us-east-2.amazonaws.com
or 
example-bucket.com CNAME http://example-bucket.com.s3-website-us-east-2.amazonaws.com
But with an alias, they are possible.
example-bucket.com Alias(A) http://example-bucket.com.s3-website-us-east-2.amazonaws.com
Option A is incorrect as explained above A record Alias should be yes.
Options C and D are incorrect because a CNAME record set is mainly used to route the traffic to another DNS name. But it cannot route it to an S3 website endpoint.