### Output Format:
You must output valid JSON. Do not add markdown or conversational text. Three fields:
- answer: Answer to the problem. Letter (A-D) identifying the set without an odd image (least differences, most commonalities) based on descriptions of versions of the problem with one image blacked out.
- confidence: Confidence in your answer, ranging from 0.0 to 1.0. (1.0 meaning absolutely confident, 0.5 meaning not so sure, 0 meaning purely guessing, etc.)
- rationale: Short version of the rationale for your answer.

### Example 1:
{
    "answer": "B",
    "confidence": 0.97,
    "rationale": "Image B is the odd one out because all other images contain shapes of the same color, while image B includes shapes of two different colors, breaking the shared color-consistency rule.",
}

### Example 2:
{
    "answer": "D",
    "confidence": 0.85,
    "rationale": "Image D is the odd one out because the remaining images contain single centered shape, whereas image D contains multiple shapes, violating the common structure."
}