A Company Collects a Steady Stream of 10 Million Data

A company collects a steady stream of 10 million data records from 100,000 sources each day. These records are written to an Amazon RDS MySQL DB. A query must produce the daily average of a data source over the past 30 days. There are twice as many reads as writes. Queries to the collected data are for one source ID at a time. How can the Solutions Architect improve the reliability and cost effectiveness of this solution?

A) Use Amazon Aurora with MySQL in a Multi-AZ mode. Use four additional read replicas.
B) Use Amazon DynamoDB with the source ID as the partition key and the timestamp as the sort key. Use a Time to Live (TTL) to delete data after 30 days.
C) Use Amazon DynamoDB with the source ID as the partition key. Use a different table each day.
D) Ingest data into Amazon Kinesis using a retention period of 30 days. Use AWS Lambda to write data records to Amazon ElastiCache for read access.