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': 'Alternate contact points along shaft are seen in \nSelect and explain. \nA. K3, B. RACE, C. Real World Endo, D. Light speed', 'role': 'user'}, {'content': "Answer: C \nExplanation: The blank design employed by the Endo Sequence file is a triangle with alternating contact points (ACP) along the instrument's ,hunk. The Endo Sequence file undergoes electropolishing and the result is visible in its mirror-like finish that remains sharper longer and mays cleaner during use.\nAbout RACE:\nDesign of the reamer with alternating\xa0 cutting edges (RACE): twisted areas alternate with straight parts. The NM surface is treated chemically resulting in an obviously smoother surface than other instruments.\nAbout 3:\n\nPositive rake angle\nVariable helical flute angle\nPeripheral blade relief\nThird radial land\nVariable core diameter\nSafe-ended tip\nWide radial lands\n\nAbout Lightspeed:\nThe LightSpeed root canal instrument has a noncutting tip and a short blade. The shaft is smooth, nontapered and very flexible. Instruments have physical resemblance with Gates Glidden drills. Also remember that term '12 peck e is associated with lightspeed instruments.", 'role': 'assistant'}]