This is a lifecycle problem, not a wording problem, and Option C gives the team a controllable lifecycle for the agent behavior. The selected option specifically C states “CoT prompting requires relatively large models; smaller models may produce reasoning chains that appear logical but are actually incorrect, leading to poorer performance.”, which matches the operational requirement rather than a superficial wording match. Small models can generate plausible but false reasoning chains. CoT helps mainly when the model has enough capacity to use the intermediate steps accurately. The implementation detail that matters is demonstrated tool usage examples plus schemas so action selection becomes constrained rather than guessed. For a production build, the prompt should align with the downstream evaluator so the model is rewarded for the behavior the system actually needs. The losing choices mostly optimize for short-term convenience; prompt-only fixes cannot compensate for missing tools, stale knowledge, or absent validation. That is the difference between an agent that works in a notebook and an agent that remains reliable in production.