{
  "meta_info": {
    "case_id": "case39_28",
    "bench_subset": "NeuroBench-Multi",
    "difficult": 1,
    "original_dataset": "Multi_QA"
  },
  "agent_input": {
    "data_path": [],
    "instruction": "Answer this standalone multimodal neurophysiology multiple-choice question: Which mapping of PSG signals to physiological evidence is correct? Options: A: All three signals measure arterial oxygen saturation. B: EEG provides eye movements, EOG provides chin tone, and chin EMG provides cortical activity. C: All three signals measure respiratory airflow. D: EEG provides brain electrical activity, EOG provides eye movements, and chin EMG provides chin muscle tone. Select exactly one option, A, B, C, or D. Return only one JSON object with the single field answer and no explanation or extra fields."
  },
  "eval_config": {
    "parser_prompt": "### ROLE\nYou are a precise JSON Extraction Engine for neurophysiological data. Your sole task is to convert natural language reports into structured JSON data.\n\n### TASK\nExtract the answer choice from the agent's report.\n- answer: exactly one of A, B, C, or D.\n\n### STRICT CONSTRAINTS (MANDATORY)\n1. Output ONLY a valid JSON object.\n2. DO NOT include Markdown code blocks.\n3. DO NOT include conversational text, explanations, or extra fields.\n4. The JSON key must be EXACTLY \"answer\".\n5. The answer value must be exactly one of \"A\", \"B\", \"C\", or \"D\".\n6. If the answer is missing or unclear, return {\"answer\": null}.\n\n### OUTPUT TEMPLATE\n{\"answer\": \"<A | B | C | D or null>\"}",
    "metrics": [
      {
        "metric_id": "knowledge_answer_accuracy",
        "type": "categorical_check",
        "target_key": "answer",
        "weight": 100,
        "params": {
          "gt_value": "D"
        }
      }
    ]
  }
}