A media company hosts a public news and video portal on AWS.

Comprehensive and Detailed Explanation From Exact Extract of AWS CloudOps Documents:

The requirement is to alert before throttling occurs. For a DynamoDB table in provisioned capacity mode, throttling happens when demand approaches or exceeds provisioned throughput. CloudWatch provides direct table metrics such as ConsumedReadCapacityUnits and ProvisionedReadCapacityUnits (and related utilization signals). Creating an alarm on ConsumedReadCapacityUnits with a threshold set close to the table’s provisioned read capacity provides an early warning that the table is nearing its limit—before actual throttling prevents reads. The alarm can publish directly to the existing SNS topic so the operations team is notified proactively.

Option C and D focus on detecting throttling after it occurs by matching throttling exceptions in logs. That is reactive and violates “before throttled.” Option B (auto scaling) may reduce the likelihood of throttling, but it does not directly satisfy the alerting requirement and “scaling events” notifications are not a reliable proxy for “approaching throttle” (and may not fire early enough depending on scaling configuration). The simplest, most direct CloudOps approach is a CloudWatch alarm on consumption nearing provisioned capacity.