Option B correctly separates asynchronous bulk work from latency-sensitive operational work. Anthropic describes the Message Batches API as a cost-effective asynchronous service for high-volume requests that do not require immediate responses. Batch requests are processed independently, normally finish within an hour, may remain pending for up to 24 hours, and are billed at 50 percent of standard API prices. Those characteristics fit standard monthly reports because they are archived after processing and have no immediate business deadline. Urgent exception reports, however, must trigger an alert within 30 minutes. The batch service cannot guarantee that deadline, even if many batches finish quickly; a workload should not use typical completion time as a service-level guarantee. Routing exceptions through the synchronous Messages API provides the real-time response path needed for alerting, while the shared JSON schema keeps downstream records consistent across both routes. Option A knowingly permits delayed alerts. Option C introduces an hourly submission delay before processing even begins. Option D meets latency requirements but wastes the batch discount on non-urgent reports. A routing layer based on document priority therefore satisfies both the cost objective and the business deadline without changing the extraction contract.

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