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': 'The components of activator are all except: \nSelect and explain. \nA. Labial bow, B. Jack screw, C. Acrylic portion, D. Delta clasp', 'role': 'user'}, {'content': 'Answer: D \nExplanation: COMPONENTS OF THE ACTIVATOR\nIt consists of the following elements:\n\nLabial bow: The wire used is spring hardened 0.9 mm stainless steel. The primary wire element of the activator consists of an upper and/or lower labial bow. It consist of horizontal middle sections, two vertical loops and wire extensions through the canine-deciduous first molar embrasure into the acrylic body.\nJack screw:\xa0 Optional (fitted to maxillary arch).\nAcrylic portion: This can be fabricated in cold cure acrylic directly on the models or a wax matrix can be made first and then invested in the flask.\n\nKey Concept:\xa0\nDelta Clasp is used in Twin Block appliance.\nReference: Textbook of orthodontics 2nd ed Gurkeerat Singh page no 519', 'role': 'assistant'}]