Answer: Deploy Amazon DynamoDB as the database solution. Provision on-demand capacity., D

## Explanation **Correct Answers: A and D** **Why A (DynamoDB with on-demand capacity) is correct:** - **Scalability:** DynamoDB is a fully managed NoSQL database that can scale automatically to handle millions of users during peak hours (4 hours in the morning) and scale down during low usage periods. - **On-demand capacity:** Provides automatic scaling without capacity planning, which is ideal for unpredictable or spiky workloads like this scenario. - **Rapid schema evolution:** DynamoDB is schema-less, allowing for rapid schema changes without downtime, meeting the data architects' requirement. - **Cost-effective:** On-demand pricing means you only pay for what you use, which is efficient for spiky traffic patterns. **Why D (S3 + CloudFront) is correct:** - **Static content hosting:** For a static single page application, S3 is the most scalable and cost-effective solution. - **CloudFront CDN:** Provides global content delivery with low latency, automatically scaling to handle millions of concurrent users. - **Cost optimization:** No need to provision and manage EC2 instances for static content. - **High availability:** S3 provides 99.999999999% durability and 99.99% availability. **Why other options are incorrect:** **B (Aurora Serverless):** While Aurora Serverless can scale, it's a relational database that doesn't support rapid schema evolution as easily as DynamoDB. Schema changes in relational databases typically require migrations and can cause downtime. **C (DynamoDB with auto scaling):** Auto scaling is good, but on-demand capacity (option A) is better for this scenario because: - On-demand doesn't require capacity planning - On-demand scales instantly to any workload - On-demand is simpler to manage for spiky traffic **E (EC2 + EFS):** This is overly complex and less scalable for static content: - Requires managing EC2 instances and Auto Scaling groups - EFS is not ideal for static web content (better for shared file storage) - More expensive and less scalable than S3 + CloudFront - Requires periodic content refresh instead of instant updates **Key AWS Services for this scenario:** 1. **Amazon S3 + CloudFront:** Best for static web content with global scalability 2. **Amazon DynamoDB:** Best for NoSQL database with rapid schema evolution and automatic scaling 3. **On-demand capacity:** Ideal for unpredictable, spiky workloads

Author: LeetQuiz Editorial Team