{
  "correct_letter": "D",
  "correct_formula": "(1/2)·m·v_0² + m·g·R·(1-cosθ_start) = (1/2)·m·v² + m·g·R·(1-cosθ)",
  "annotation": "Environment: g=-9.81, F_drag=0.0\nGround: mu_s=0.7, mu_k=0.6\nTireSphere: d = 1.0, e = 0.6, theta_start = 0°, v_0 = 4.0\nTrack_0: R = 2.0, e = 0.3, theta_min = 0°, theta_max = 360°, mu_s = 0.0, mu_k = 0.0",
  "choices": [
    "a_c = v²·cosθ / (R·sinθ)",
    "PV = nRT",
    "F = (3/4)·E*·√(R·d³)",
    "(1/2)·m·v_0² + m·g·R·(1-cosθ_start) = (1/2)·m·v² + m·g·R·(1-cosθ)"
  ],
  "correct_index": 3,
  "physics_type": "Circular",
  "seed": "Circular|benchmark/circular/0"
}