Final answer:
The correct answer to which services use AWS edge locations is option A. Amazon CloudFront and option B. AWS Shield. AWS edge locations are designed to deliver content with lower latency by caching data closer to users.
Step-by-step explanation:
The services that use AWS edge locations are Amazon CloudFront and AWS Shield. Edge locations are used to reduce latency in content delivery and to provide DDoS protection, unlike EC2, RDS, and ElastiCache which do not use edge locations.
Amazon CloudFront is a content delivery network service that securely delivers data, videos, applications, and APIs to customers globally with low latency, and it uses edge locations to cache content closer to the end-users. Another service that benefits from edge locations is AWS Shield, which is a managed Distributed Denial of Service (DDoS) protection service that safeguards applications running on AWS.
Services such as Amazon EC2, Amazon RDS, and Amazon ElastiCache do not utilize edge locations directly. Instead, they operate in AWS regions and availability zones, which are designed for different purposes than edge locations. Edge locations are specifically for speeding up the delivery of content and protecting against DDoS attacks at the network edge, rather than hosting primary infrastructure services.