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: Dental
[{'content': 'For a dental hand instrument with a formula of 10-8.5-8-14, the number 10 refers to ________. \nSelect and explain. \nA. The width of the blade in tenths of a millimeter, B. The primary cutting edge angle in centigrades, C. The blade length in millimeters, D. The blade angle in centigrades', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The ﬁrst number is the width of the blade or primary cutting edge in tenths of a millimeter (0.1\xa0 mm).\xa0\nThe second number of a four-number code indicates the primary cutting edge angle, measured\xa0 from a line parallel to the long axis of the instrument handle in clockwise centigrades. The angle is\xa0 expressed as a percent of 360 degrees. The instrument is positioned so that this number always\xa0 exceeds 50. If the edge is locally perpendicular to the blade, then this number is normally omitted,\xa0 resulting in a three-number code.\xa0\nThe third number (second number of a three-number code)\xa0 indicates the blade length in millimeters.\xa0\nThe fourth number (third number of a three-number code)\xa0 indicates the blade angle, relative to the long axis of the handle in clockwise centigrades.\n\nSturdevants operative dentistry 7th edition page e2', 'role': 'assistant'}]