This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'According to Pederson difficulty index, what is the difficulty level of an impacted tooth\nwhich is lying horizontally, at Level III and position C? \nSelect and explain. \nA. Minimum difficulty, B. Moderate difficulty, C. Very difficult, D. Not impacted', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Pederson difficulty index based on Pell and Gregory classification:\n(A) Spatial relationship:\nMesioangular = 1\nHorizontal = 2\nVertical = 3\nDistoangular = 4\n(B) Depth:\nPosition A (highest portion of crown of 8 is above occlusal line of 2nd molar)\xa0=1\nPosition B (higher portion of crown of 8 is above CEJ of 2nd molar) = 2\nPosition C (highest portion of crown of 8 is below CEJ of 2nd molar) = 3\n(C) Relation\xa0with ascending ramus:\nLevel 1 (mesiodistal width between 7 and ascending ramus is sufficient to accommodate mesiodistal\xa0width of 8) = 1\nLevel 2 (space slightly short to accomodate the entire mesiodistal width of 8) = 2\nLevel 3 (space very less\xa0to accomodate the entire mesiodistal width of 8 – tooth almost within ascending ramus ) = 3\nDifficulty score = A+B+C\nScore 3-4 = minimum difficulty\nScore 5-7 = moderate difficulty\nScore 8-10 = very difficult.\nOther difficulty indices are: WHARFE Score, Parant and Modified Parant scale and using WAR lines.', 'role': 'assistant'}]