{
  "correct_letter": "D",
  "correct_formula": "ΣM_ext = 0",
  "annotation": "Environment: g=-9.81, F_drag=0.0",
  "choices": [
    "W = ΔE_k = (1/2)·m·v_t² - (1/2)·m·v_0²",
    "I = V / R",
    "ΣF = m·Δv / (Δt·cosθ)",
    "ΣM_ext = 0"
  ],
  "correct_index": 3,
  "physics_type": "AtRest",
  "seed": "AtRest|benchmark/at_rest/8"
}