What is the MOST cost-effective way to achieve this?
Create a CNAME record in Amazon Route 53 that points to the CloudFront distribution URL.
Create an ALIAS record in Amazon Route 53 that points to the CioudFront distribution URL.
Create an A record in Amazon Route 53 that points to the public IP address of the web application,
Create a PTR record in Amazon Route 53 that points to the public IP address of the web application.
Explanations:
A CNAME record cannot be used at the root domain level (naked domain) in Route 53, and while it can be used for subdomains, ALIAS records are preferred for integration with AWS services like CloudFront.
An ALIAS record in Route 53 allows mapping the domain (www.example.com) directly to the CloudFront distribution without needing an actual IP address. It is optimized for use with AWS services and does not incur additional charges for DNS queries.
An A record pointing to the public IP address of the web application would not utilize CloudFront, thus bypassing its benefits like caching and geographic distribution, and it can also lead to higher costs due to direct access.
A PTR record is used for reverse DNS lookups, not for directing traffic to a web application. It is irrelevant in this scenario as it does not resolve to an IP address that users can access.