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 mm).\nThe second number of a four-number code indicates the primary cutting edge angle, measured from a line parallel to the long axis of the instrument handle in clockwise centigrades. The angle is expressed as a percent of 360 degrees. The instrument is positioned so that this number always exceeds 50. If the edge is locally perpendicular to the blade, then this number is normally omitted, resulting in a three-number code.\nThe third number (second number of a three-number code) indicates the blade length in millimeters.\nThe fourth number (third number of a three-number code) indicates the blade angle, relative to the long axis of the handle in clockwise centigrades.', 'role': 'assistant'}]