Exam AWS Certified Database - Specialty topic 1 question 331 discussion

Answer is D https://aws.amazon.com/dynamodb/standard-ia/

D is the answer. sub digit milisecond latecy = DynamoDB

most cost efficient while others require some more cost for provision and manage the DB

DynamoDB = single digit ms latency and IA for cost-efficienct

Correct C- S3 is a cost-effective storage

I think not there is an answer that match the question requirements. Because A and B support single-digit millisecond latency but cost expensive and C: S3 is a cost-effective storage dose not support single-digit millisecond Keyword : "single-digit millisecond latency on average" and "MOST cost-effective solution" A: Only DynamoDB it can provide single-digit millisecond latency . But on-demand capacity mode doesn't Purchase reserved capacity. B: Amazon ElastiCache for Redis is fast in-memory data store that provides sub-millisecond latency. If choose node size memory more 120 Gg is cost expensive C: Use Amazon S3 Standard-Infrequent Access . S3 is a cost-effective storage solution but Amazon Athena to queries and get results in seconds but may not meet the single-digit millisecond latency requirement xD: is wrong. DynamoDB not has Standard-Infrequent Access