The correct answer is B. Pay-as-you-go. A proof of concept should start with minimum commitment, flexible usage, and the ability to scale as demand becomes clearer. Pay-as-you-go pricing is appropriate because it allows the organization to pay based on actual model consumption rather than reserving dedicated capacity upfront. This is ideal when usage is uncertain, experimental, or expected to change during testing. Provisioned Throughput Units are better for predictable, high-volume production workloads that need reserved capacity and consistent throughput. Batch API is designed for asynchronous large-scale processing, not an interactive agent PoC. Microsoft 365 Copilot is a separate productivity service and not the Azure OpenAI pricing model for a custom agent solution.