A Company Maintains an Application Responsible for Processing Several Thousand

A company maintains an application responsible for processing several thousand external callbacks each day. The company's System administrators want to know how many callbacks are being received on a rolling basis, and they want this data available for 10 days. The company also wants the ability to issue automated alerts if the number of callbacks exceeds the defined thresholds. What is the MOST cost-effective way to address the need to track and alert on these statistics?

A) Push callback data to an Amazon RDS database that can be queried to show historical data and to alert on exceeded thresholds.
B) Push callback data to AWS X-Ray and use AWS Lambda to query, display, and alert on exceeded thresholds.
C) Push callback data to Amazon Kinesis Data Streams and invoke an AWS Lambda function that stores data in Amazon DynamoDB and sends the required alerts.
D) Push callback data to Amazon CloudWatch as a custom metric and use the CloudWatch alerting mechanisms to alert System Administrators.